if i'd guess, this is happening on the outside of the first joint of the thumb. usually this happens because parts of your fingers, especially near joints, arent used to impact. this happens with bass players as well when playing percussively.
i've never had the common hand/finger problems because i've been doing kung fu for years before i started playing. the hand conditioning that is undertaken is quite beneficial for a musician.
what i would suggest is basic hand conditioning. what you can do is get a thick telephone book (but i'd prefer like a sandbag because it'll shape somewhat to your hand) and just sit it on a table or other sturdy surface and just firmly hit it with your palm, fingers spread apart (dont go crazy, you can just hold ur hand above about a few inches and let gravity do the rest). probably do it about 20-30 times like a few times a week (takes only about a minute or so) and u'll be conditioning the surface of your hand and you'll find that those hand injuries will be less common.
Let me ask you a question, how are your fingers hitting the keys? I say this cuz it sounds like ur playing the keys like u would hit a drum. If that's the case, then that's ur problem. Keys shouldn't be played with brute force like a drum. You will hurt urself and the instrument. Try keeping ur fingers more on the keys and when u want to play louder, just apply pressure or turn up the volume. Don't pick your hands up and then slam em down on the keys.
I agree with T-Block, I've been playing 38 years and never had a problem with my fingers. If you watch my videos on youtube you'll notice I don't play with force on the keys.
this probably isnt him trying to play keys like a drum. what often happens with beginners is that at first speed comes with added force because you have to exert more force to move faster because its not as natural. over time you can have the speed + the delicate touch, but at the beginning that combination isnt there. its true on any instrument. (although everyone may not experience that or the same problems/effects of it)