I have been playing guitar around a year or so. And I have had callues (not sure how to spell it) that worked well for me. Meaning, I got a calleus after a short while and my finger were good from then on. Well, now my finger calleus are going away. And I have been playing constantly, like multiple hours a day.!!

Also, skin is peeling off my fingertips...Are my finger rebuilding a stronger calleus?

I did recently put on new strings, like maybe a month or two ago...And they are a far heavier gauge than the former strings...

Is this normal? Am I getting better calleuses?

My fingers always look like that my fingers never really hurt unless I play for like 6 hours straight but I think you fingers are always getting stonger but thats just my thought.

Holy Knight of the Crusading Order of the Stratocaster.

MIA Fender Stratocaster
MIA Fender Telecaster
MI? Fender TC-90

Fender Hot Rod Deville
Blackstar HT5, HT40

various pedals
I think that your callous (I think this is how you spell it) are just regenerating so to speak.

Just like any other cells in the human body, they die and reproduce, correct? If so, then there's your answer.

My callouses do this quite often...well not quite often, but often enough. It doesnt bother me at all and it shouldn't really affect your playing.
your fingers probably hurt because you're playing multiple hours a day when your fingers aren't really used to it yet. Your calluses will peel and regenerate after a while and become stronger so that you can play for a longer time without feeling much discomfort.

by the way it's either callus or callous, according to wikipedia.
Nor less I deem that there are Powers
Which of themselves our minds impress;
That we can feed this mind of ours
In a wise passiveness.

i tried posting an in depth answer earlier but UG crapped out on me.... long story short. it is cuz of the string thickness, when i went from .48 - .09 to .70 - .011's my fingertips started hurting a LOT i had totally forgotten about it. i recommend continuing to play on heavy strings but in shorter bursts and make sure to rest plenty as that is when callouses actually form.