Talk to General Surgeon on A Small Ball On Hand

Hi A small ball has formed at the back of my hand where the wrist ends and the back of my palm starts. This ball has formed before but it usually went away in some time. But this one is bigger than the earlier ones and is not decreasing in size. It does not cause any pain but now it does hinder the movement of my hand backwards. This has started to worry me a little. I have no idea to what sort of doctor should I consult with for this. I have attached few pictures below as well.