“Can hearing loss in one ear be fixed?”

If the sudden hearing loss is caused by something like an earwax impaction, it can certainly be treated. If the sudden hearing loss is related to a nerve-type loss, there may not be much to do medically after about a week. While the hearing may not return, you may be a candidate for a specific type of hearing aid technology known as a CROS. I would recommend visiting an ear, nose, and throat specialist to evaluate the sudden hearing loss as a first step.

Yes it can. I would suggest that you make an appointment with an audiologist.