Hi Nice Day!
I had this too! Hard little blistery things, but they started off as a small patch on my palm and I ended up with raw skin on both palms and finger tips (OUCH!) I went to a dermatologist he said it was "dermatitis"(wow, like I hadn't worked that out already)and sent me on a 6 month wildgoose chase (no dairy, all sorts of meds and creams-even suggested anti depressants- etc) nothing worked. Got so bad I ended up bandaging my hands (they were unsightly and they REALLY hurt!)
Anyway to cut a long story short had to go to my family doctor with a totally unrelated problem and he saw my hands and said "At bedtime put on hydro-cortisone cream and a pair of examination gloves" the result after a couple of nights was nothing short of miraculous! Anyway if your finger gets any worse try the same with just a bit of plastic wrap over your finger! Know it sounds weird but it really does work!
Daughter in law has a patch of psoriasis on her back that flares up occassionally she puts her cream on at bed time wraps the wrap around her body and she says it always works too.
Anyway it's a cheap and easy solution that I hope works for you too!
All the best.