A small (about 1 mm) Lump suddenly appeared in my penile shaft (near the head). What is it?

It doesn't really hurt when I touch it. Its a really small solid lump near my head (the other head). I've never had ual , but I've been enjoying with myself *ahem*. I researched a bit and a site says it could be lymphocele (my umption due to what I see and feel) which is not really serious and will go away with time (as they say). Anyone have any other idea?