Swollen red bump on lower lip

Patient: I have a red bump on my lower lip near my vermilion border. It has swollen the lip in the area. It is a little painful and tender to the touch. I have had a problem with acne my whole life (I currently see a dermatologist). I am in college and it is finals week so I have been busy and a little stressed out. What do you think that it is?

Symptoms: Some pain. It is more annoying than anything

Images:
Swollen red bump on lower lip-1

Doctor: