ANSWER:

These sheikhs are either genuine sheiks who recite the Quran and ruqya and they must have the patient present in front of them or they are soothsayers who deal with Jinn and black magic. 

Going to such people nullifies islam if one believes them.

Going to the first type is permissible.  

 

I have a friend. She was very good . But now a days she behaves very weird. I discussed about it with some of my friends they said these all are consequences of black magic. Will it be a sin if I go to another sheikh to get rid of it? Besides if it really the consequences of black magic then what should i do in the way of ISLAM please sheikh Help me in this.