What Causes Bump Growing Under The Cuticle Of The Thumb Nails?

I have noticed a small, growing bump growing from under the cuticle outward toward the front of my thumb nails on each hand. The one on the left is quite large and the one on the right is still growing. it is hard, not sore, does not hurt to touch. Just curious. I usually wear acrylic nails but haven't in a while, but not sure what the drill will do to these bumps.