My circumvallate papillae are extremely inflamed and my tongue has a yellow mucus on it. there is also some blisters in my mouth. what could this be?

Infections?: Mostly bacterial or fungal in nature, imbalance in bacterial flora creat that kind of infection , certain meds. And antibiotics can cause that imbalance .. Are you on any meds?

Needs evaluation: You may have one or multiple causes for the symptoms that you describe. You would need to be personally seen by a dentist and\or physician to go over your medical history and personally examine you in order to determine the cause(s) and treatment.

Canker sores : Canker sores are the most common oral lesions. The cause is unknown. Topical medications otc applied directly, mouthwashes, and oral medications can relieve pain or inflammation. Rec.: if not comfortable see a dentist for soft tissue laser treatment.