El corte en mi mano es pequeño, pero duele un poco.

Both are grammatically correct, but there is a nuance:

• en la mano – very common, neutral: on/in the hand (the owner is usually clear from context).
  
  • Me corté la mano. – I cut my hand.
• en mi mano – adds a bit of emphasis to my hand, often used:
  • to contrast with someone else’s: El corte en mi mano es pequeño, pero el tuyo es grande.
  • when you just personally want to stress it’s my hand.

In everyday speech, many native speakers in Spain would naturally say:
El corte en la mano es pequeño, pero duele un poco, especially if it’s obvious whose hand you’re talking about.

Mano is one of the classic exceptions to the “-o = masculine, -a = feminine” pattern.

• It is always feminine:
  
  • la mano – the hand
  • una mano – a hand
  • mi mano / tu mano / su mano – my/your/his/her hand
  • esta mano – this hand

You must say la mano, never el mano. Native speakers don’t think about the rule here; they simply memorize it.

Spanish chooses between ser and estar based on how the speaker sees the quality:

• es pequeño (with ser)

  • Describes a general or inherent characteristic: the cut is small (by nature; that’s simply its size).
  • This is the normal, neutral choice for size of things like wounds, objects, etc.

• está pequeño (with estar)

  • Suggests a temporary state or a comparison to another time/standard:
    
    • La camiseta está pequeña. – The T-shirt is (too) small (for me/now).
    • ¡Qué grande está el niño! – The child is so big now! (compared to before)
  • With a cut, está pequeño would sound odd or forced. You’re not usually thinking of a cut as temporarily small.

So, El corte en mi mano es pequeño is the natural way to talk about its size.

Adjectives agree with the noun they actually describe:

• Here, pequeño describes corte, not mano:
  
  • el corte → masculine singular
  • So we say pequeño → masculine singular to match:
    
    • El corte es pequeño.

If you were describing the hand, then the adjective would agree with mano (feminine):

• Mi mano es pequeña. – My hand is small.

Yes, that’s perfectly correct and very natural.

• El corte en mi mano es pequeño…

  • Subject: el corte en mi mano
  • Predicate adjective: pequeño

• Es un corte pequeño…

  • Subject: (Él / Ese) implied – It
  • Predicate noun phrase: un corte pequeño – a small cut

Meaning-wise, they’re almost identical.
The version with un corte pequeño just packages “corte + pequeño” together as one labeled thing (a small cut), instead of “the cut is small”.

Spanish normally drops subject pronouns when they’re clear from the verb form.

• In duele un poco, the verb duele is 3rd person singular. The subject is understood from context:
  • (El corte) duele un poco. – The cut hurts a bit.
  • You don’t need to say Él duele un poco; that would sound wrong here.

So Spanish doesn’t need a separate pronoun like English it. The context plus the verb ending already tell you what’s doing the action.

Doler is used in two main ways:

1. With an explicit subject (like your sentence):

   • El corte duele un poco. – The cut hurts a bit.
   • Duele un poco. – It hurts a bit. (subject understood from context)

2. With an indirect object pronoun (very common):

   • Me duele la mano. – My hand hurts / My hand is hurting me.
     
     • Subject: la mano
     • Indirect object (the person in pain): me
   • Le duele la cabeza. – His/her head hurts.

In your sentence, you’re focusing on the cut itself, so using duele on its own is fine.
If you wanted to emphasize that you are feeling the pain, you might say:

• El corte en mi mano es pequeño, pero me duele un poco.
  – The cut on my hand is small, but it hurts me a bit / but it hurts a bit (to me).

The little word un changes the nuance:

• duele un poco

  • Literally: it hurts a little / it hurts a bit.
  • Neutral description of some pain.

• duele poco

  • Literally: it hurts little.
  • Usually sounds like it doesn’t hurt much – emphasizing that the pain is not very strong.

So:

• El corte… duele un poco. – There is some pain.
• El corte… duele poco. – It hardly hurts / It doesn’t hurt much.

Yes, but the meaning shifts slightly:

• corte – specifically a cut made by something sharp (knife, paper, glass, etc.).
• herida – a more general wound or injury (could be a cut, but also a scrape, puncture, etc.).

Both are common in Spain:

• El corte en mi mano es pequeño… – The cut on my hand is small…
• La herida en mi mano es pequeña… – The wound on my hand is small…

If it’s clearly a cut from something sharp (like a knife), corte is usually more precise.

In Spanish, it is standard to put a comma before conjunctions like pero when they link two clauses or mark a clear pause:

• El corte en mi mano es pequeño, pero duele un poco.
  
  • Clause 1: El corte en mi mano es pequeño
  • Clause 2: duele un poco

The comma shows the contrast: it’s small, but it hurts a bit.
Writing it without a comma is generally considered incorrect or at least non-standard in careful writing.

Spanish has two different words:

• mi (no accent)

  • Possessive adjective: my
  • Comes before a noun.
  • Example: mi mano, mi casa, mi coche.

• mí (with accent)

  • Pronoun used after prepositions: me.
  • Example: para mí – for me, sin mí – without me.

In your sentence, mi is describing the noun mano (my hand), so you must use the possessive adjective without an accent:

• El corte en mi mano es pequeño, pero duele un poco.