ey!

I'm a bit confused! Can someone tell me the difference between:

- Retinol OTC products
- Retinoids: differin, Retin A,...
- Isotretinoin creme

They're all related to Vitamine A, is it just the amount of active ingredient or what?

And a related question for one of the DR's on this board:
I have like 3 wounds on my face for about 6 weeks now due to TCA peeling. My derm told me not to worry but although they seem way less red then the first weeks, they don't see any smaller...should I be worried? I already went under a therapeutic laser to let them heal faster and nicer and my derm gave me 10% L-ascorbic drops for hyperpigmentation on the wounds! But I'm like really worried!
And 3 pharmacists I went too told me NOT to put Isotretinoin creme on it, but my derm said I could because of cellregenaration....who to believe?