
These bumps on the backside are very common. You need to get a very stiff body brush or back brush or even a rough nail brush…and some shower gel. in the shower put some gel on the brush and scrub your bum cheeks. Its to get rid of the build up of dead skin cells. Obviously dont make yourself sore, but it doesnt matter if the existing spots bleed. Rinse thoroughly and dry, then massage in some emollient body cream. Doesnt have to be expensive stuff but the oat base creams are very good. Do this on alternate days especially just before bed and it should gradually get rid of the problem . If the spots start again then just resume the scrubbing and moisturising.
They bleed tremendously if they are picked at…which you have discovered, so dont pick or even touch them.