MTO SHOCKER: Stylist Shows Pics Of Ashanti's 'FILTHY' Bikini Bottoms . . . They Have . . . ERRR . . . BROWN STAINS On Them!!!!

R&B singer Ashanti's stylist is upset with her. She was "lent" a very expensive bikini, and returned the bottoms covered in BROWN STAINS.

We're not going to SPECULATE what that brown stuff is. Here's what the stylist said: