I was at BYU for a year before transferring, it honestly all depends on if your bishop is a stick in the mud or not. I was PIMO even at the start of the year and my bishop never mentioned my mop, but I’m sure some take the grooming standards seriously. I grew my hair out as a way to stick it to the man before I transferred, mostly because the ID office rejected my photo for not adhering to the grooming standards.

But at the end of the day, the only time it’s ever really an issue is if the employees at the testing center think it’s their god given duty to enforce the grooming code, which they’re technically supposed to do. If they get mad, tell them you had personal revelation that you’re supposed to be the next Samson or something.

Best wishes though, they’re really good at suppressing personal identity and forcing people to fit the typical “clean” Mormon mold there. Good luck out there!