Well FWIW I would always recommend a tuneable bodhran and to slacken off the tension after playing. Carting a bodhran to and around a festival or session in the summer is bound to affect the skin.
And if you want to feed the skin, a small amount of neatesfoot oil goes a long way. Seriously a small amount, enough to grease yer hands (not wet them). Just rub yer hands over the skin, the outside is easiest, and playing will get it on the inside. I buy "Pure" Neatesfoot Oil, if it says "compound" it is adulterated with mineral oils to stop it freezing in cold weather, avoid. The pure variety goes like soft butter when below about 5^oC, use a spatula. It is good for joints so rubbing it into your hands is beneficial. Again, sparingly.