I suggest "burn". When you sear something, you normally use a very hot metal object such as a frying pan, or a hot knife. "Consume" is a little too complete and thorough to be a synonym.

Agree with Peachey: Consume has a similar meaning but a great difference in degree. "Consume" would imply that the person was engulfed in flames and burnt to ashes (by pain or guilt), whereas "sear" really means "burn," and more precisely, "burn on the outside."