If you lose your temper even once over the issue, your child is bound to associate the bed-wetting with feelings of guilt and shame, even more than he or she currently has.
If you are in a rush and do not have time to launder the soiled sheets each morning, consider buying a few replacement sheets and double-rinse the soiled sheet later on that day. Keeping cleaning rags handy in your child's closet will also aid the convenience of cleanup. If you prepare in anticipation of an accident, you will be less likely to lose your temper and can remain truly supportive and sensitive.