toddler cold question.

My 21 month old son started a preschool this week and has gone 3 mornings and came home today and started developing a bad cold. His nose is so stuffy, he's coughing so hard he gags, and I just noticed over the last hour his upper lip is swollen. What does that mean? I've given him tylenol and Motrin for the next dose. also what can I do to help a 21 month old get over a bad cold? Thank you 😓