Surge back refers to the sudden increase or return of something, usually in a forceful or powerful way. Some synonyms for surge back include resurge, rebound, reappear, renew, and recover. Resurge emphasizes the idea of something coming back stronger and more powerful than before. Rebound suggests a quick recovery after a setback or decline. Reappear refers to something returning after a period of absence or disappearance. Renew emphasizes the sense of revitalization or rejuvenation. And recover suggests a return to normal or original state after a decline or illness. These words can be used interchangeably depending on the context and intended meaning.