Well done .... , but as you asked for proofreading, I can leave you some comments which I wish they would be useful for u in future translations :)

The title: you should omit "her", "I 'm the opposite to what they see" is enough and clear, by adding "her" you are confusing the English reader.

they called her head stubborn and strong (use big T "They", omit "head")
nothing can affect her
no one in this world can
tell her what to do
or what she dreams for or wish for (Why would she dream or have a wish, it's a new sentence)
She doesn't need anything

Deep in the heart I'm the opposite of what they see her (just "Deep inside i'm, and again OMIT "her" ..."
may God help her and heal her wounds (help me with healing my wounds)
sometimes one smile hides away a big wound (sometimes smiling is hiding a deep wound)
sometimes there are things we don't like to show

Deep inside I'm hurting a lot (Most of time I feel pain inside)
million things I hold back killing me (a million hidden internal issues are so killing me,
that I wish I could talk to someone and get relieved,
but my self-esteem holds me back)

And the rest of ur work is just fine,,, but please take care of using capital letters,for example, you kept using the capital I inappropriately.

And finally, sorry for the long message and good luck :)