Cluster Of Moveable Lumps Beneath Front Bottom Teeth, Pimple With White Heads, Pain In Cheek Area Post Zpack. Serious?

I ve been to the doctor three times for a cluster of lumpbs beneath my front bottom teeth , there seems to be about four of them, small, and can t be seen unless I depress the floor of my mouth with my tongue and then it looks like a pimple with a white head. Initially they instructed me to keep an eye on it and see if it got worse or doesn t go away. It didn t go away, so I returned to the doctor, who said it was an infection and gave me a Z pack. Several days later, I noticed a pain in the cheek area and went back, and he changed the antibiotic to Augmentin , which has relieved my cheek symptoms, however, it has not done anything to the lumps under my front teeth seemingly. They are small and moveable and seems to be roundish and very close together. I m concerned they re obviously something more serious. Any help or direction would be greatly appreciated.