What can happen if i wake up on a ventilator after a minor operation?

Not clear: We would really need more details. Part of the concern would be why you needed to be on a ventilator at all after what you describe as "minor" surgery. Exactly why we rarely use that term. Any surgery has complications. There are also rare complications of anesthesia. Doctors, nurses and respiratory therapists would be treating that inciting event in the hopes they could rapidly remove support.

Minor discomfort: Unless you have significant heart, lung or other disease, you should be able to get off the ventilator immediately or shortly after any surgery.