You are talking about the glass and not the mirror frame I am guessing. I know of no frame that is held on by 3m type tape. If yours was repaired using tape, I don't think it was done correctly.
Is your mirror a Velvac? If so, google Velvac and take a look at how it is assembled. It can be fairly complicated but there is a way to repair it.
2016 Arctic Fox 25Y, 2016 F350 4x4 DRW, 6.7
2008 Mobile Suites RE3: Sold
2005 Monaco Dynasty Diamond IV: Sold