Glycolic Acid?

To preface I have hidrinitis on my lower back and under my arms. I also have insulin resistant PCOS and enteral histaminosis... So I heard that glycolic acid can help with my dark patches under my arms and such but I can hardly shave my underarms without getting a bad flare up or just feeling pain in general. However, summers coming and I'd like to clear up some of the dark spots because they seem to be growing bigger and bigger and lots more noticeable. Will glycolic acid be too harsh? I ordered the acid from the ordinary and plan to use it in other places but I just want to know yalls experience with sensitive skin and glycolic acid. Lately I just feel so ugly with HS so I'm trying to do some things to clear up some of the spots