Lump inside mouth

For the past month or so I have noticed a lump inside my mouth. It's located just inside the bottom lip, approximately in front of my canine teeth. It swells to the point that it becomes painful to chew food. I have tried using a pin needle to pop it, and when I do that, a slightly yellowish fluid bursts until the lump is completely deflated. However, within 24 hours the lump is full of the fluid again and I have to pop it again. What might this issue be?

[Jerome Tsang, DDS]

I would consult with your dentist immediately.  Its sounds like its an abscess and you should get it treated as soon as possible.  Abscesses can be dangerous, even life threatening, and can spread very rapidly.  

I would recommend to continue to pop it to prevent the abscess from spreading (as you are draining it).  You could also put some warm salt water in your mouth to draw the pus out.  

But most importantly, go see your dentist to get proper treatment.  Don't delay.