overexaggerate

From over- +‎ exaggerate, perhaps specifically influenced by overstate and/or overdo.

overexaggerate (third-person singular simple present overexaggerates, present participle overexaggerating, simple past and past participle overexaggerated)

1. To exaggerate, to overstate excessively.

   "That math test was so hard, nobody could have passed it! Albert Einstein couldn't have done it! Our professor probably had no idea how to solve those equations! I mean-"

   "I get it, OK? Quit overexaggerating!"

• Since exaggerate already denotes excess, overexaggerate is considered redundant and therefore proscribed by some authorities.^{[1] [2]}