Have I permanently burned my face by leaving Glycolic acid 70% on for 12 mins? (Photo)

It is difficult to say, but it does appear that you have caused postinflammatory erythema (redness) and postinflammatory hyperpigmentation (PIH). It is not clear how many days you are post-treatment. You would be wise, however, to consult with a board certified aesthetic dermatologist asap to be started on topical prescription medications to suppress the inflammatory redness (which often evolves into PIH and occasionally scarring) and the PIH. The physician may also decide to combine this with a series of in-office superficial peels to suppress the pigmentation. Given the COVID virus pandemic, you should attempt to contact a specialist asap, at least perhaps starting with a telemedicine consult, so that you can be more adequately evaluated. For you, it is now after the fact, but for other readers I think it is important to strongly emphasize once again what I have been cautioning readers of my columns for years: Chemical peels and other treatments intended for the hands of experienced doctors should not be done at home from YouTube instructionals and Amazon purchased medical grade products intended for the hands of physicians who have undergone years of training to acquire their experience with these technqiues and strong medication products. Best of luck to you.