Mi hija se dio un golpe en la mejilla con la puerta del armario, pero no le pasó nada.

Because darse un golpe is a very common Spanish expression meaning to knock/hit oneself, usually accidentally.

• Mi hija dio un golpe would more naturally mean my daughter gave a blow/strike to something or someone.
• Mi hija se dio un golpe means my daughter bumped herself / knocked herself.

The se shows that the action happened to her own body.

It literally means to give oneself a blow, but in natural English it usually corresponds to:

• to bump oneself
• to knock oneself
• to hit oneself
• sometimes to bang a part of the body

It often suggests an accidental impact rather than a deliberate action.

Spanish very often uses a light verb + noun structure where English might prefer a single verb.

So instead of saying something like she cheek-hit herself (which Spanish does not do), Spanish naturally says:

• se dio un golpe = she got/had a bump/knock

This structure is extremely common:

• darse un golpe
• darse un susto
• dar un beso
• dar un paseo

Because in Spanish, with body parts and clothing, the definite article is often used instead of a possessive when the owner is obvious.

So:

• en la mejilla = on the cheek
• not usually en su mejilla, unless you want to stress whose cheek it was

Since the subject is already mi hija, Spanish does not need to repeat the possession.

Here en marks the place on the body where the impact happened.

So se dio un golpe en la mejilla means:

• she hit herself on the cheek
• she got a bump on the cheek

Spanish often uses en for the location affected by a hit or injury.

Here con is best understood as with / against the object that caused the impact.

So:

• se dio un golpe ... con la puerta del armario = she hit herself ... on/against the wardrobe door

In English we might prefer against, but Spanish commonly uses con in this kind of sentence.

Del is the contraction of de + el.

So:

• del armario = of the wardrobe / closet / cabinet

That means:

• la puerta del armario = the wardrobe door or the closet door

Spanish uses this structure very naturally where English often uses a noun-noun combination.

Because the expression is pasarle algo/nada a alguien = for something/nothing to happen to someone.

In this structure, the person affected is treated like an indirect object, so Spanish uses:

• me, te, le, nos, os, les

So:

• no le pasó nada = nothing happened to her

Here le refers to mi hija.

Because Spanish uses negative concord. That means multiple negative-looking words can appear together in the same sentence.

So:

• no le pasó nada literally looks like not ... nothing
• but it simply means nothing happened to her

This is completely normal in Spanish.

Compare:

• No vi a nadie = I didn’t see anyone
• No dijo nada = He/She didn’t say anything

Yes, you could, but it sounds more marked or literary.

• No le pasó nada is the normal, everyday way to say it.
• Nada le pasó puts more emphasis on nothing.

For most learners, no le pasó nada is the version to remember and use.

Because both actions are seen as completed events in the past:

• se dio un golpe = a single incident
• no le pasó nada = the result after that incident

The preterite is the normal tense for telling what happened in a sequence of events.

If you used the imperfect, it would sound like background description rather than a completed event.

Not literally in the strictest sense. It is a very common way to say that she was fine, she wasn’t injured, or nothing serious happened to her.

So even though she did hit her cheek, the sentence means that there were no real consequences.

Usually, yes. In Spain, armario commonly means:

• wardrobe
• cupboard
• closet
• cabinet, depending on context

In this sentence, la puerta del armario most naturally suggests the wardrobe/closet door.