You have an issue with anime anatomy here. If you have a problem with drawing nipples, I think you shouldn't draw a boob that's more than 50% exposed. To make matters worse, there is a protrusion where the nipple should be, but no nipple. It's like it... ran away, or was surgically removed. The overall effect is jarring. I suggest you either move up the towel and leave the protrusion there or, if you want to be edgy, just draw the nipple.