Why do your lips get chapped when your sick?

Your body is dehydrated and usually your nose is plugged up, forcing you to breathe out of your mouth.Why do your lips get chapped when your sick?
If you have a stuffed up nose you have to breath through your mouth and all the air dries out your lips. this happens to me all the time.Why do your lips get chapped when your sick?
because your body is normally dehydrated when you are sick