Treatment for cystoid macular edema is directed at the cause, and may vary from post-cataract edema (anti-inflammatories including steroid or non-steroidal anti-inflammatory eyedrops, tablets and injections around or into the eye), diabetes (injections into the eye or laser treatment to the retina), or vitreous traction (where surgery is offered).
Vision often improves significantly when the edema resolves, however you are correct in asking if it will ever return to normal. Unfortunately vision quality may never be completely normal again. Even if the visual acuity returns to 6/6, there are often minor changes in color perception, or contrast sensitivity that may be detected with fine diagnostic tests.
You should discuss your specific situation with your attending ophthalmologist.