(Sorry if this is the wrong place to post, im new!!!)

Ok, so i have two African clawed frogs and theyre about a year old, however i recently left for uni and let my parents take care of them whilst i was away, on my return for the christmas break i noticed on of my frogs has small faint spots all over his back (theyre both albino) and the other does not. I change their water every week use ammonia stopper solution and safe tap water solution - their tank is always clean. He eats perfectly fine and moves around as normal, there is no change in his behaviour however im worried as he did not have this before and the other one doesnt have it. could it be a disease?! being at uni makes it hard for me to be able to give him the right treatment and time he needs if so
i will post a photo later
PLEASE HELP!