"like" means "similar" Their house looks like ours. (nearly the same, similar) "as" means "different, to be something or somebody else" They were dressed as clowns. "As" is used when we name a profession of a person. She works as a teacher.

There is no big difference in some circumstance, but they are different words in general with different applications.

He was doing very well as if he was a professional skill worker.