In the back left side of my gums on the bottom, it is squishy and not painful but I can feel it. Also it looks like a blister was there?

Chronic abscess. A chronic gum abscess may be painless, but is sometimes the most destructive. This is because it becomes walled off by a fibrous sack called a granuloma, which is only diagnosable with an x-ray imaging. See a dentist for treatment, do not delay.
What to do... If it heals and does not return I would not worry... however if it does not heal or returns, I would see your dentist for an evaluation.
Abscess-see ur DDS. either dental or periodontal abscess.
Abscess ? It may very well be. Just because your not in pain does not mean you don't need treatment. Please call a local dentist for an appointment.