If it was working before, it's probably not the temperature limiting feature. WHen the water was turned off, the spool-valve part in the pressure balance valve may have become stuck when the water was turned back on. Depending, it may just need cleaning and lubrication, or you may have to replace it.
The temperature limit is normally easy to adjust. Take the handle off, remove the eschution plate, and adjust the screw (depends on the brand, this is typical). Should take all of a couple of minutes if the handle comes off easily. Servicing the spool valve would take a little longer, but not necessarily.
Now, if your valve is quite old, it may not have that safety feature built-in, and it could just be some crud caught in the valve or debris screen.