Ingrown hairs, boils, or cysts? Appeared after shaving, caused by chafing from wearing pads. Feel like pea sized hard lumps beneath skin. More info in comments
Nfsw my butt, the damage to my back from adhesive. This is the nasty open sore level damage my back has from adhesive. Unfortunately my insurance is refusing the liquid medication topical despite the obvious need to avoid the adhesive.
