How long can Tretinoin .1% used twice only in two large peas size amounts each time, stay active in the skin?

I was given Tretinoin .1% along with Melamin and Melamix (hydroquinone 4%) and told to mix the Tretinoin with the Melamix two days on two days off. I only did two days, my skin couldn't take it. I peeled for the next 5 days. Now my skin has taken on a rough look around my mouth and on my chin. It is tight, dry, and sensitive. I feel like I aged overnight but it seems like the texture got worse over the course of two weeks. It has now been 3 weeks and I am still sensitive to lotions and washing.

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