First have you tried just wiping it away to be sure it's not just on his nose?
Second,I almost think if it were actually coming out, the tortoise would be rubbing its face/nose to try and remove it.
If it doesn't wipe off, slowly and gently see if you can pull it out.
Your tortoise is beautiful. He seems to have quite a bit of pyramiding though. Maybe you can tell us how he is kept? Temperatures and humidity? Soaking?