If you think he still has shed on him, especially his face but him in a cloth snake bag..or tube sock get it wet with warm water stick a wet paper towel in there for good measure. Close off the sack stick him in his cage for a few as he moves around to try and get it the moisture and the cloth will add in taking that shed off
If he has RI it really depends how far along it is. He will still eat until he starts feeling really bad. Bubbles, raspy noises, fluid in his mouth are all signs of RI