A serpentine belt is not supposed to be glazed. A glazed serpentine belt usually causes slipping of the pulleys. If the belt is just glazed and not cracked, you should use a 400 grit wet/dry sandpaper and remove the glaze from the surface.
The most sensible thing is to simply replace it. Unless your budget is severely restricted, or it's an especially rare or expensive belt, replacing a belt is usually a straightforward and relatively cheap procedure -- especially compared to the damage it could do if it snaps.
A glazed serpentine belt will need to be replaced, normally when the belt has more than three or four cracks an inch, has deep cracks or is frayed,or has a glazed look. The belt is inexpensive to replace and usually need to be replaced around 50,000 miles. A car will usually make a squel sound under the hood.
If the serpentine belt gets glazed, it will slip and not provide the proper circulation to keep the engine cool. Fix it before putting on a new serpentine drive belt.
The best to do about a glazed belt is to replace it. A serpentine belt is a vital part of the vehicle and to be safe and not to find yourself stranded in the future, go to your local mechanic shop and get your belt replace as soon as possible.