I've searched the net for some sort of idea of what this dream could mean, but I can't find anything.
So in this dream, I'm standing at my basin brushing my teeth. Then, the side of my jaw starts getting red and swells up half of my face, before shrinking back into a really hard feeling lump. I touch it, and pus starts pouring out. I start vomiting pus and bile, and I can't move my mouth to yell out for help because if I do, I just vomit more pus.
It's really gross, I know but it's puzzling me as to why this dream keeps occurring. I've had the same dream every night for about a week.
Any advice would be very appreciated.
Thank you all.

Scary dream. The answer lies in the meaning of the symbols. Here are links to the definitions at dreamdoctor.com:

teeth problems: dreamdoctor.com/dream-dictionary/definitions/teeth.html
disease: dreamdoctor.com/dream-dictionary/definitions/disease.html
illness: dreamdoctor.com/dream-dictionary/definitions/illness.html
vomit: dreamdoctor.com/dream-dictionary/definitions/vomit.html
can't scream: dreamdoctor.com/dream-dictionary/definitions/can-t-scream.html
recurring dreams: dreamdoctor.com/daily-dream/recurring-dreams.html

You didn't reveal anything about yourself or your waking life in your post, so it's hard to say with certainty what exactly caused it. However, the symbols are very consistent. You are feeling bad about something in your waking life. It may have to do with your feelings about your appearance or how you feel you are being perceived in your waking life. You either don't know how to and/or can't release your distasteful or toxic emotions about the situation. It makes you feel even worse about yourself.

The message of your dream is that you need to talk to someone about how you are feeling about this "tumorous" growth of negative emotions. It is building up within you in an unhealthy way. If you don't have a close friend or family member with whom you can confide, you should consider talking to a therapist or counselor about it. You don't like the feelings you have about whatever it is that has happened or how it makes you feel, but once you let them out, the healing can begin.

If you can't identify what it is, think back to when you first started having the dream. Because recurring dreams are always about unresolved feelings about issues in your waking life, what was going on or happened to you that made you feel the way you do in the dream. Feelings IN dream are never disguised, so how you feel in these dreams is how you feel about their subject in your waking life.

Please share what it was, so we can all better understand what your dream was about. In the meantime, I hope that this has been helpful.

Good luck!