
Best to let a vet decide- but it may be a hystiocytoma- a benign tumour. In many cases they resolve naturally within 2-3 months.
http://www.marvistavet.com/html/body_histiocytoma.htmlInfo and pic in the link, you do need to be sure what you are dealing with though, so first port of call must be vet.
On my dogs, I have tried both removal and allowing nature to resolve. I would now favour nature! One of my girls had one on her chin at - this was surgically removed and she had the scar all her life, another girl was left to nature and no scar. They are quite common in pups/young dogs.
Best wishes.