Quarter-sized lump on inside of thigh, surface is smooth, shiny, light purple. It's hard, goes quite deep under skin. Slightly tender. No drainage.

Cyst. This may be a sebaceous cyst if it is the only time you have had this. Many people can get multiple of these in the same area over the years. I would not recommend trying to squeeze it because it will make it worse. Apply warm compressses for 10 min twice a day. If very sore see your md for antibiotics that will improve the symptoms even though it is not a true infections.