Over doing it in any new pastime is a rite of passage. You’re excited and want to give it your best and with stringed instruments, this means discomfort. I remember using all sorts of things to try and toughen my fingers up quicker, but nothing beats playing and little and often, as @Dad3353 says above, the way forward. It’ll come, but not in days, in fact you’ll probably not notice the improvement until you go to do something that was impossible seemingly the day before and is now achievable (it wasn’t the day before, it was weeks previous). I had Bert’s Play in a Day, I think everyone did back then. My nephew, who is a formidable player and left me in his wake once I showed him the blues scale, once played in a backing band for Bert.