100 mg of minocycline twice a day and tretinoin cream is helping acne but causing extremely dry skin! will topical vitamin e oil help?

Acne: The topical tretinoin can dry the skin, so I would suggest using less of it or using a skin moisturizer like eucerin or any glycerin based cream. Vit E may help but is expensive in comparison.

Yes: Any type of moisturizer will help. You should apply at least twice daily and make sure the one you use during daylight has a sunscreen built in as well. If the oil form is too "oily" for your skin and re-plugs pores, use the ointment or cream.