This is always a very annoying thought. When we get better, we look at older art and think it looks bad, but if start to redraw old pages it's never ending cycle. I drew first pages of my comic few months ago and I already see there are many mistakes and I would draw some things better and differenly. It's a hell cycle, because we could just redraw pages for eternity.
I personally tried to learn that you improve as artist every day. You will always be better than before and if you want to make a long story, you just can't go bak to old pages everytime you see something bad. Try to look at it as simpsons. Earlier seson were really rough and then got better, but they didin't rework them. It's part of you artist history and proof you get better.
If you really wnat to rework story from beggining, i would suggest to start totally over, like remaster or reboot.