Skin on upper lip

hi, just a query is the skin on the upper lip naturally thinner than the rest of the face?

I’ve been using jolen hair bleach on my upper lip for about 4 years now and i’ve read that a possible long term side effect of it is thinning of the skin. Im paranoid that my upper lip skin may have gotten a lot thinner.

this is the article that talks about jolen thinning skin:

any advice or comments is much appreciated thanks!