Teething or Sick?

Hi mamas! My son will be a year old in 2 weeks (🥺) For the last couple of days he has had so much yellow mucous just pouring out of his nose. There’s so much that I can hear him stop and swallow it. Today he’s started coughing intermittently, it sounds like a dry cough. He also has a light red rash around his mouth. Nothing on his hands or feet. No fever. He does have a tooth coming in. Advice please? ❤️