Dressage Riders: Your Opinion? Thanks right now because I didn't have room to say it in the details.?

This one horse was donated to my school's riding program (we can do riding for P.E.) but we decided not to keep him. So we gave Luigi to this one trainer who used to work at school, but left to start her own barn that wasn't so centered around academics. (Also Luigi has sarcoids between his front legs and on his face, but they don't touch the girth and we put a fuzzy on his bridle) A week later, I started taking lessons with her because I didn't get enough one-on-one instruction at school and I wanted to compete. So I started riding Luigi and I really liked him (and still do, alot). Then I said something about how I planned to compete Luigi in dressage in front of her. (I plan to ride at first level, then hopefully move up to second next year.) But then my school trainer told me that I couldn't show him because of how he looks. He looks amazing from a distance because you can't see his sarcoids. He's a really pretty horse, even with sarcoids. I think it is okay to show him, do you?