Antibiotics causing swollen lymph nodes under jawline?

Ok so my body is fighting off two infections: an abscessed tooth(front left) and two boils in a very personal area. Two nights ago I had a resting pulse of over 110 bpm and got scared and went to the ER. They gave me .5 xanex for my racing heart (doctor said it was anxiety), 2 antibiotics: clindamycim 300 and sulfamethoxaz-tmp ds 800–160 (which is generic for bactrim), and percocet 5 for pain. Long story short (too late, I know) I started my medication yesterday morning, this morning I woke up and my left lymph node under jawline is pretty swollen, is it just doing it’s job or should I be worried? Also the xanex doesn’t seem to be helping my racing heart feeling. Any ideas? Should I go back to the ER?