Hey Matt
Good advice from the others in this thread. Get to the vet for sure. My 7 yr old Cane had one of these before xmas that required surgery because we didn't catch it right away. They scraped it off and then used his 3rd eye lid to cover the eye while healing. They basically sewed his eyelid or membrane to the top of his eyebrow, it looked so bad my wife fainted in the waiting room and hit the floor like a scak of hammers.
Just this Saturday i noticed Cane was squinting his right eye, i took him to the vet right away, and it was bad news. Another ulcer, this time in the other eye. I put the e-collar on him right away, not taking any chances and don't want to have surgery again. So I have to give him eye meds EVERY 3 hours. So I am back to setting my alarm clock for 2:00 am, and 5:00am. I went through 3 weeks of this at xmas and can't beleive i am going through it again, but what can you do.
Much love to Mya! You can get through this but it will require a lot of patience and love. But you are a boxer owner so you should have lots of both.