... so does that mean the engine is just less efficient, or has it essentially become a paperweight, and is worse than useless for the purposes of keeping a giant metal bird in the sky? (yes I realise these planes are designed to be able to land with one engine out, or two if you're Tom Hanks and near a freezing cold river)
This plane is a 74, so it's got 4 engines and IIRC there was at one point a trans-atlantic flight from SFO or LA (with passengers, this one was cargo) that had a compressor stall on takeoff and they just KEPT GOING on 3 engines and made it almost all the way to Heathrow before diverting due to the less efficient fuel use.
EDIT: sorry didn't notice sibling comment mentioning this exact incident, here are some links for the lazy
There isn't a single reason for a compressor stall, so neither there is a single possible outcome. The pilots are generally instructed to reduce power level until the surging stops; if the damage is too great that won't help and the engine must be shut down. All passenger aircraft are certified to be fully controllable with an engine out, but having it happen is usually treated as an emergency. (With some notable exceptions like flight BA 268, look it up.)
