I wouldn’t react just yet. The noise could be from stuck shed over nostrils. Opening the mouth doesn’t seem good but i didnt see it and i dont know how often he is doing that. Do you see mucous from the nose or mouth?
Your temps are good, id keep humidity up 60% to 70% when you know he is pre-shed. Why are you saying he just ate? Did you feed him while he was in blue? Has it been 48 hrs since he ate? If so soak him in warm water for 15 min. Use a tote with a lid. Keep the water 90 and keep it above 80. Work on the shed after he soaks and softens up. He might rub some off himself.