What is this wierd bump on my shin?

I have this weird bump on my shin when i sit a certain way, and it has been there since i started on all my medications for lyme disease. I was wondering is it from the medication, or is it a type of cancer? it is squishy, i can like poke them, they are just there. But when i poke them, they move a lil, like squish ball or something. can anyone help?