A pimple inside your mouth is called a mucocele. This condition develops when a tiny salivary gland becomes blocked. You may notice a fluid-filled bump on the soft tissue. In some instances, it can rupture spontaneously. However, avoid attempting to pick or pop it yourself. More often than not, a mucocele will resolve independently without intervention. If the issue persists, it's advisable to consult a dentist for a professional evaluation.