I have over the last 6 months developed what appears to be callous type lumps under the skin in the centre of my palms. These have kept growing and are now restricting the straightening out of my hands. If I force the straigthening of my hand I feel a tearing sensation in the area. They are centred around the centre two fingers. I have attached photos of these lumps. Any feedback on what may be causing this and whether they may continue growing would be appreciated.