I Am Prescribed Xtraglo Tab After I Had A Lazer

I am prescribed Xtraglo tab after I had a lazer sitting Q-swt . Which is been given to me for hirsuitism (face) and freckles. As cosmetologist said it will reduce the growth of my facial hair. So I am concern how it can only act on my facial hair alone without any effect on the hair growth of my head? and some where it is also written that it enhances the growth.
Please give our opinion.