Tengo una ceja un poco diferente de la otra, pero casi no se nota.

In Spanish, tener is very commonly used to describe physical features, characteristics, and things a person has.

So Tengo una ceja... literally means I have one eyebrow..., but in natural English we would usually say something like One of my eyebrows is...

This is completely normal Spanish:

• Tengo el pelo rizado = I have curly hair
• Tengo los ojos azules = I have blue eyes
• Tengo una cicatriz = I have a scar

Here, tengo is just the natural way to introduce a feature of your body.

Because the speaker is comparing one eyebrow with the other one.

• una ceja = one eyebrow
• la otra = the other one

So the structure focuses on the contrast between the two eyebrows:

• Tengo una ceja un poco diferente de la otra
  = One of my eyebrows is a little different from the other

If you said mis cejas son un poco diferentes, that would mean my eyebrows are a little different, which is also possible, but it sounds less specific and slightly less personal in focus. The original sentence highlights one eyebrow in particular.

Spanish often uses the definite article with otro/otra when it means the other one.

So:

• la otra = the other one
• el otro = the other one (masculine)

In this sentence, la otra stands for the other eyebrow. Spanish often leaves out the noun when it is obvious:

• una ceja ... la otra
  literally: one eyebrow ... the other

You could think of it as an ellipsis:

• la otra ceja → shortened to la otra

Because ceja is simply a feminine noun in Spanish.

That is why you get:

• una ceja
• la ceja
• la otra

You just have to learn its gender as part of the word. Many body-part words are feminine, though not all of them:

• la ceja = eyebrow
• la mano = hand
• la nariz = nose
• el ojo = eye
• el brazo = arm

Un poco means a little or slightly. It softens the statement.

So:

• diferente = different
• un poco diferente = a little different / slightly different

It makes the sentence sound less strong and more natural:

• Tengo una ceja diferente de la otra = One eyebrow is different from the other
• Tengo una ceja un poco diferente de la otra = One eyebrow is a little different from the other

This is a very common way to make descriptions more gentle or less dramatic in Spanish.

The most traditional and widely recommended combination is diferente de.

So:

• diferente de la otra = different from the other

You may also hear diferente a in real Spanish, and many native speakers use it, but for learners, diferente de is the safest and most standard choice.

Similar patterns:

• distinto de = different from
• separado de = separate from

So in this sentence, de is the expected preposition.

In Spanish, adjectives usually come after the noun.

So:

• una ceja diferente = a different eyebrow
• una ceja un poco diferente = a slightly different eyebrow

This is the normal order in Spanish. English often puts adjectives before the noun, but Spanish usually puts them after.

Compare:

• un coche rojo = a red car
• una casa grande = a big house
• una ceja diferente = a different eyebrow

Literally, it is something like it almost doesn’t show or it is almost not noticeable.

In natural English, the best translation is usually:

• you can hardly notice it
• it’s barely noticeable
• it almost doesn’t show

Breakdown:

• casi = almost
• no = not
• se nota = it shows / it is noticeable / one notices it

So casi no se nota means that the difference exists, but it is very hard to notice.

Here, notarse / se nota means to be noticeable, to show, or to be apparent.

The verb is notar, which often means to notice:

• Noto una diferencia = I notice a difference

But in the form se nota, Spanish often uses it in a more impersonal way:

• Se nota = it shows / it’s noticeable / you can notice it

So:

• pero casi no se nota
  = but it’s hardly noticeable

This is a very common expression in Spanish.

Not really in the usual reflexive sense.

This se is better understood as part of an impersonal or passive-like construction. It makes the sentence less direct and more natural:

• Se nota = it is noticeable / you can notice it

It does not mean that something is noticing itself.

For learners, the most useful thing is to remember se nota as a fixed, common expression meaning:

• it shows
• it’s noticeable
• you can tell

Other similar examples:

• Se ve mucho = It shows a lot / It’s very noticeable
• No se entiende = It isn’t understood / You can’t understand it
• Se dice mucho = It is said a lot / People say it a lot

Because the idea being treated as noticeable is singular.

The implied subject is something like:

• la diferencia
• eso
• el hecho de que una ceja sea un poco diferente

All of those are singular ideas, so the verb is singular:

• se nota

If the subject were clearly plural, then you would use se notan:

• Las diferencias se notan = The differences are noticeable

But here the speaker is referring to the overall asymmetry as one single thing, so se nota is the natural choice.

Yes. Distinta is a very natural alternative.

So you could say:

• Tengo una ceja un poco distinta de la otra

This means almost the same thing:

• diferente = different
• distinta = different / distinct

In everyday Spanish, both work well here. Diferente may feel a bit more common for many learners, but distinta is perfectly natural.

A broad Spain pronunciation would be roughly:

TEN-go OO-na THAY-ha oon PO-co dee-fe-REN-te de la O-tra, PE-ro KA-see no se NO-ta

A few useful pronunciation points:

• ceja: the c before e in most of Spain sounds like th in think, so ceja sounds like THE-ha
• j in ceja is a strong throaty sound, like the ch in Scottish loch or German Bach
• casi has a normal k sound at the start: KA-see
• se nota flows together smoothly: se NO-ta

If you are learning Spain Spanish, ceja is one of those good words for practicing both the th sound of c before e/i and the Spanish j.