Some Constipation on Accutane?

I've been experiencing a bit of constipation on accutane, basically I'm just much less regular than I was before I started the treatment (10mg daily). Is this normal? Will this side-effect disappear after the treatment? My concern is that, if accutane is supposed to permanently change how my skin works, could it also permanently change how my bowls work? If not, could someone explain WHY not? (Also-I've tried drinking a ton more water in case dryness was the problem-it hasn't really helped).