Learn Hardcore Japanese: purofiiru wo sukosi kaete kara, atarasii nihonzin no forowaa ga huete kimasita. - Since I changed my profile a bit, the number of new Japanese followers has started to increase.

プロフィールを少し変える uses を because 変える is a transitive verb (“to change something”). The “something” that gets changed is marked with を, the direct object marker.

プロフィールを変える = to change (my) profile
プロフィールが変わる = the profile changes (by itself / as a result of something)

So using が here would require switching to the intransitive verb 変わる, and the meaning/structure would change:

プロフィールが少し変わってから、…
“After the profile (somehow) changed a bit, …” (it sounds like the change happened to it, not that you changed it)

What exactly does 変えてから mean? How does verb-て + から work here?

変えてから is verb-て + から, and in this pattern から means “after …” (a time sequence).

変える = to change
変えて = te-form
変えてから = after changing …

So:

プロフィールを少し変えてから、…
“After (I) changed my profile a little, …”

In this use, から does not mean “because”; it marks that the second thing (フォロワーが増えてきました) happens after the first thing (プロフィールを変える).

What’s the difference between 変えてから and 変えたあと(で)?

Both 〜てから and 〜たあと(で) can mean “after doing …”, but there are some nuances:

変えてから
- “after changing (and from then on…)”
- Often implies a clear starting point and that the next action/state starts right after and may continue from that time until now.
- Fits well with things that have been true since that event:
  プロフィールを少し変えてから、フォロワーが増えてきました。
  “Ever since I changed my profile a bit, followers have been increasing.”
変えたあと(で)
- More neutral “after I changed it (and then I did X)”.
- Focus is more on sequence and less on “and it’s been this way ever since.”

Here, because 増えてきました already has a “gradually up to now” feeling, 変えてから matches nicely.

If I said プロフィールを少し変えたから、新しい日本人のフォロワーが増えてきました, would that be wrong? What would it mean?

That’s grammatical, but the meaning changes:

プロフィールを少し変えてから、…
= “After I changed my profile a bit, …” (time sequence)
プロフィールを少し変えたから、…
= “Because I changed my profile a bit, …” (cause/reason)

With dictionary/ta-form + から, the usual reading is “because/since …”. So:

プロフィールを少し変えたから、新しい日本人のフォロワーが増えてきました。
“Because I changed my profile a bit, new Japanese followers have started to increase.”

So it shifts from a neutral “after that, this happened” to a more explicit “this happened because of that.”

What nuance does 少し add here? Is it modifying “profile” or “change”?

少し means “a little, a bit” and here it modifies the verb 変える:

プロフィールを少し変える
= to change the profile a little (make a small change)

So the idea is “I didn’t do a complete makeover; I only changed it a bit.”

It does not mean “a small profile”; it’s about how much you changed it, not the size of the profile itself.

What’s the difference between 少し and ちょっと in this sentence?

In this context, both 少し and ちょっと are fine and very close in meaning:

プロフィールを少し変えてから、…
プロフィールをちょっと変えてから、…

Nuances (general tendencies):

少し
- Slightly more neutral / “standard”.
- Often used in writing and speech.
ちょっと
- Very common in casual speech.
- Can sound a bit more colloquial or softer.

In this sentence, you can safely treat them as interchangeable with no big meaning change.

In 新しい日本人のフォロワー, which word is modifying which? Is it “new Japanese followers” or “Japanese new followers” or something else?

Think of it with brackets:

[日本人のフォロワー] = followers who are Japanese
新しい [日本人のフォロワー] = new [followers who are Japanese]

So the structure is:

日本人のフォロワー: “Japanese followers” (followers, and those followers are Japanese)
新しい modifies that whole phrase: new Japanese followers.

So the natural English reading is “new Japanese followers” (new followers, and those followers are Japanese).

Why is it 日本人のフォロワー and not 日本人フォロワー?

In Japanese, to say “X-type Y”, the usual pattern is Noun + の + Noun:

日本人のフォロワー = followers who are Japanese
日本の会社 = Japanese company
学生の友だち = (my) friends who are students

日本人フォロワー (without の) is not ungrammatical, but:

It sounds more like a compound word / label, something you might see in marketing, tags, or very casual written speech.
It has a more “category name” feel: “Japanese-followers” (as a group label) rather than a plain description.

In ordinary sentences, 日本人のフォロワー is more natural.

Why is が used with フォロワー, and what would change if I used は instead?

が marks the subject—the thing that is increasing:

新しい日本人のフォロワーが増えてきました。
= “New Japanese followers have (started to) increase.”

Using が here typically:

Introduces what is increasing as new information.
Focuses on “it is the new Japanese followers that have increased.”

If you used は:

新しい日本人のフォロワーは増えてきました。
This makes 新しい日本人のフォロワー the topic: “As for new Japanese followers, they have increased.”

That can imply a contrast, e.g. “New Japanese followers have increased (but maybe other kinds of followers haven’t).” So が is more neutral for simply reporting the change.

What does 増えてきました actually mean? Why not just 増えました?

増えてきました is 増える (to increase) in te-form + くる:

増える = to increase
増えてくる = to start increasing / to have been increasing (up to now)
増えてきました (polite past) = “has come to increase / has been increasing (up to now)”

Nuance:

Emphasizes a gradual change over time that has reached the present.
Often feels like “they’ve started (and continued) to increase.”

By contrast:

増えました = “(they) increased”
- More like a simple completed event; less focus on the process or on “up until now.”

In this sentence, 増えてきました matches the idea that since changing the profile, the number has been building up.

Does きました here still mean “came”? Or is it something different?

Here きました is from 来る (くる), but it’s being used as a grammatical helper (auxiliary), not as the literal verb “to come (to a place)”.

In patterns like:

Vてくる / Vてきました

くる expresses a change or action that moves toward the present / toward “here” in time or situation. So:

増えてきました
= “has come to increase” → “has been increasing (up till now)”

So you shouldn’t translate きました here as “came”; it’s part of the aspect/nuance of the verb “increase.”

What’s the difference between 増えてきました and 増えていきました?

Both are Vて + くる / いく patterns, but the “direction” is different:

Vてくる: change up to now / toward here
Vていく: change from now on / away from here (into the future)

So:

増えてきました
= They have been increasing up to now; you’re looking backward from the present.
増えていきました
= They kept increasing (as time went on); often describing a past sequence going further away from some point.

In your sentence, you’re talking about how the follower count has built up since you changed your profile and up to now, so 増えてきました is the natural choice.

Why isn’t “I” mentioned anywhere? How would I say it if I want to be explicit?

Japanese often omits the subject when it’s clear from context. In this context, it’s naturally understood that:

The profile is your profile.
The followers are your followers.

So it’s unnecessary to say “I” or “my”.

If you really want to be explicit, you could say:

私のプロフィールを少し変えてから、新しい日本人のフォロワーが増えてきました。
“After I changed my profile a little, new Japanese followers have started to increase.”

Usually, though, the original sentence is more natural and not ambiguous in context.

The sentence ends with 増えてきました, which is past polite. But the situation feels ongoing. Is it talking about the present or the past?

〜てきました in the past polite form often means:

“It has (up to now) been doing X.”

So it describes:

A process that started in the past,
Continued up to the present,
And often still holds now.

So 増えてきました suggests:

They have been increasing and
As of now, the number is higher than before.

It’s similar to English present perfect:
“New Japanese followers have been increasing (since I changed my profile).”

What is the politeness level of this sentence? How would it look in casual speech?

The sentence uses polite past (〜ました), so it’s at the standard polite level:

増えてきました。 (polite)

In casual/plain form, you’d say:

プロフィールを少し変えてから、新しい日本人のフォロワーが増えてきた。

The grammar and nuance stay the same; only the verb endings change from polite (〜ます / 〜ました) to plain (〜る / 〜た).