Yeni ayakkabılar yüzünden topuğum kızardı.

Yüzünden means because of, due to, or on account of.

So:

• Yeni ayakkabılar yüzünden = because of the new shoes

A useful thing to know: yüzünden often suggests a negative result.
That fits this sentence, because the speaker’s heel became red/irritated.

Compare:

• yağmur yüzünden = because of the rain
• trafik yüzünden = because of traffic

For a more neutral or formal because of, Turkish also uses nedeniyle.

Ayakkabılar is the plural of ayakkabı (shoe).

• ayakkabı = shoe
• ayakkabılar = shoes

In English, we usually say new shoes for a pair, and Turkish does the same here.
So yeni ayakkabılar naturally means new shoes.

Because topuğum means my heel.

The base word is:

• topuk = heel

To say my heel, Turkish adds a possessive suffix:

• topuk + -(I)m → topuğum

Two things happen here:

1. The possessive suffix is -um here because of vowel harmony.
2. The final k in topuk changes to ğ before a vowel-initial suffix.

So:

• topuk = heel
• topuğum = my heel

This kind of consonant change is very common in Turkish.

This is a common Turkish sound change called consonant softening.

Some words ending in p, ç, t, k change when a vowel-initial suffix is added:

• kitap → kitabı
• ağaç → ağacı
• kanat → kanadı
• topuk → topuğu

Then with my:

• topuğu + m → topuğum

So the k → ğ change happens because the suffix begins with a vowel.

Because topuğum is the subject here, not the object.

The sentence structure is basically:

• [Because of the new shoes] [my heel] [became red]

So:

• topuğum = my heel → subject
• kızardı = became red

If it were the direct object of another verb, then you might see topuğumu.

For example:

• Topuğumu gördü. = He/She saw my heel.

Here, though, my heel is the thing that turned red, so no accusative ending is needed.

Kızardı is from the verb kızarmak.

• kızarmak = to become red, to redden, to blush

So topuğum kızardı means:

• my heel became red
• my heel got red
• in natural English here: my heel got irritated/red

The ending -dı / -di / -du / -dü is the simple past tense.

So:

• kızardı = became red

Because the verb agrees with topuğum, not with ayakkabılar.

The real subject is:

• topuğum = my heel

The phrase yeni ayakkabılar yüzünden just gives the reason:

• because of the new shoes

So the verb is singular because my heel is singular:

• topuğum kızardı = my heel became red

Turkish often puts the verb at the end, and other parts of the sentence can move around depending on emphasis.

Here the order is:

• Yeni ayakkabılar yüzünden = because of the new shoes
• topuğum = my heel
• kızardı = became red

This is a very natural Turkish order.

You could also rearrange it for emphasis, for example:

• Topuğum yeni ayakkabılar yüzünden kızardı.

That still means the same thing, but the focus may feel slightly different.

Usually, yes. Yüzünden often implies that something bad or inconvenient happened.

That is why it works well here:

• Yeni ayakkabılar yüzünden topuğum kızardı.
• My heel got red because of the new shoes.

If the result is positive, Turkish more often uses:

• sayesinde = thanks to

Example:

• Senin sayende işi bitirdim. = Thanks to you, I finished the work.

So a learner should remember:

• yüzünden → often negative
• sayesinde → positive

Both can make sense, but they are not exactly the same style.

• kızarmak means to become red / redden
• kırmızı olmak literally means to become red

In Turkish, kızarmak is often the more natural verb for skin turning red, blushing, or something reddening.

So:

• Topuğum kızardı sounds very natural.

Topuğum kırmızı oldu is understandable, but it sounds less idiomatic in this kind of situation.

Yes. Kızarmak can mean:

• to blush
• to turn red
• to redden

Examples:

• Utanınca kızardı. = She blushed when she got embarrassed.
• Güneşte yüzüm kızardı. = My face got red in the sun.

So in this sentence, the idea is not emotional blushing, but physical redness/irritation.

Because of vowel harmony.

The word topuk has the last vowel u, so the possessive suffix follows that pattern:

• -(I)m can appear as -ım, -im, -um, -üm
• here it becomes -um

So:

• topuk → topuğum

This is a very common Turkish pattern.

Yes. Even though kızardı literally means became red, in context it can strongly suggest:

• rubbing
• irritation
• soreness
• skin chafing from new shoes

So the Turkish is describing the visible result (redness), but the understood meaning can be broader: the heel was irritated by the shoes.

Because the verb kızarmak already contains the idea of becoming red.

English often says:

• got red
• became red

Turkish uses a single verb:

• kızarmak = to become red

So:

• topuğum kızardı literally already means my heel became red

There is no need for an extra verb like get or become.