Ugh! Last night, I found a red lump inside the top of my thigh, it was bright red and felt hot. It looked like it had two white "heads" on it and I know I shouldn't have, but I did, I had a little squeeze! (God it hurt, but I won't learn my lesson!) They popped and I won't go into lurid detail, but it made even cast-iron stomach me feel a bit sick - Vesuvius IYKWIM. Today its not as big, but is still very red and very tender, and is still inflamed around the main lump - and I can feel swelling around it still. Its about a centimeter across.
Any ideas what it is, how I got it and what I should do (apart from leave it alone, obviously )