Suggest Treatment For Hard Painless Spot On Big Toe

I noticed this hard painless spot under my big right toe way back in 1997. An exition was performed on it in 2000, the site got healed after some months but the problem persists, this time with a slight pain especially when I step on a hard object such as a stone. I use a sharp razor blade to cut through the upper skin when it becomes too hard and that's precisely then the pain are felt more.The spot however doesn't increase in size, am worried what this could be and how I can completely get rid of it.



Thanks, Mercy (Limbe - Cameroon)