hi ..thanks for your query..
If there is a non scarred area ,hair should grow back! However, if you are unable to visualize the area completely,you should undergo a check up for the same.With the kind of boil you mentioned,I would not think of a scar anyway,but whenever you have any similar kind of a boil/erution in an hairy area ,always remember that not touching it is the fastest way to let it heal..it is very important for a hairy area where infections tend to be recurrent and persistent and where scarring would mean lost of hair.
Even now, hair growth can be stimulated by using mild short course topical steroids
and hair growth stimulating agents like 2%Minoxidil