Yes, they can rub their nose raw (or even completely off), and it can become infected. An antibiotic ointment without painkillers (neosporin) is generally safe--confine it to the wounded area, as it can cause scales to slough.
If you see any real sign of infection around the area, a vet will be needed, as that would require systemic antibiotics.
Step one is to figure out what he's rubbing his nose ON, so he can be stopped. Iguanas and other lizards usually face-rub on glass or mesh surfaces that they can see through, but you said he's in a bathroom...so what is he rubbing on?
Does he have elevated hide boxes, hollow logs, etc, that he can retreat into, to get out of sight?
If you see any real sign of infection around the area, a vet will be needed, as that would require systemic antibiotics.
Step one is to figure out what he's rubbing his nose ON, so he can be stopped. Iguanas and other lizards usually face-rub on glass or mesh surfaces that they can see through, but you said he's in a bathroom...so what is he rubbing on?
Does he have elevated hide boxes, hollow logs, etc, that he can retreat into, to get out of sight?