I’ve had some weird skin phenomena happening and I haven’t gotten an ID. I have a large brown splotch of skin that appeared below my knee two months ago and hasn’t faded, changed shape or color, or been irritated or itchy. It looks like a light birth mark or bruise. Just prior to its appearance (a couple days), I noticed a burn-like sensation on my thumb, despite not actually burning myself, though I had been in the sun a little, without sunscreen, but did not get burned at all. When I squeezed my thumb, blisters formed on the skin surface, than merged into one large burn-like blister. Smaller blisters appeared on nearby fingers. These healed and became small brown spots, which “spread” to both hands/fingers. These disappeared quickly. The spot on my leg seems similar, though much larger, and it persists. I’m not even sure these are related! What could these be?