I found a small, black mole-looking thing that is raised on my 4 year old Maltese's front leg. I found this about 2 months ago, but today it started bleeding a little when it was scratched. It is very small(3/4mm) and hasnt grown since i saw it 2 months ago. It is hard to the touch and it seems like it hurts Bella(my dog) when I touch it. The bleeding is also pretty minimal, and stopped after a few minutes. Should i be worried about this? Does anyone know what this could be?