I discovered a hard lump in my navel and removed it with twizzers and with a lot of difficulty it came out. The top that was exposed was black and very hard however, the end of it was about 3/4 inches long and soft. It was rather scary and now I wonder if I should take it to a doctor.
Hi, thanks for sharing your health concerns with Chat Doctor!  If I were your treating Doctor for this case of an inverted hard navel lump, I would come up with two possibilities