5 year old with swollen cheek from mouth sore, it might be from abcessed tooth?

My 5 year old son has a mouth sore/ulcer on the inside of his cheek and he had a slight fever before bedtime so i gave him pediatric paracetamol. the next morning, he woke up with the side of his face swollen (same side as the mouth sore). He lets me touch his swollen cheek, which feels firmer at at he part near his nose/mouth. He does not have an allergic reation to paracetamol cos i have been giving it to him for his fever before. His fever is gone and he also has an appetite, so I assume it does not have anything to do with his teeth or gums. But i think it is worth mentioning that 3 weeks ago, he has been complaining about his gums hurt and it was swelling because food got stuck inbetween his molars. it got better after brushing/flossing, although it took 2 days..  I took him to the GP and we were prescribed antibiotics to reduce the swelling but no futher advise was given. I would really appreciate it if someone can give me an explanation or advise on what to do next.  

[Jerome Tsang, DDS]

You may want to go to a dentist to get it evaluated.  It could be an abscess of some sort.