How can I find out if I have an alien implant?

I think it's in the front right part of my right shin.

I never had an injury there, but there is a lump just under the skin.It is the size of a small screw head, just under the skin but not into the muscle. It never gets bigger, docent hurt, isn't a scar. I am really healthy and have had many things left in my skin that my body has rejected ( stitches, rocks, metal and wood slivers, even a piece of glass that my body pushed out over a year after it was embedded in me.

I know a lot about this stuff and am truly baffled by this. It has been there for over twenty years. I have tried to pop it, scrape it off, no effect. I'm tempted to just cut it off but am a little Leary.

I don't have any money to speak of.

Any ideas?