My push mower started to knock a little for a long time then while I was mowing one day it started blowing oil out the exhust or carb. When I turned it off the oil still ran out of it. It was running ruff so I turned it off. It started back when I tried later but still lost oil. Can this be fixed or do I have a blown engine?

I've never seen oil come out of the carb before.

Exhaust yes... crankcase vent yes. Worn guides, worn, broken or stuck oil control rings and even a clogged vent can do it.

9 times out of 10 (if not more) on an older engine means its worn out.