I've had this weird thing happening in my armpit, which happened around 5 days ago. I have 3 dark lines (color of a bruise almost) going across my armpit (not up and down) and only one of them is kind of scabbing so it might be that my skin is rubbing or something. But the other lines are not scabbing and when I run my finger across them, nothing feels like it's raised. I was thinking it might be a reaction to my deodorant, but it's only my left armpit. And this did not happen immediately after shaving either. I don't feel any lumps or bumps under the skin either. It also burns quite a bit so i'm not sure what's going on. Any insight is highly appreciated. There are some lines associated with scarlet fever, but I don't have that.

Rpr