Health - Dangers of dosing Diphenhydramine before a minor operation?

[Sameriel]

So SWIM was thinking about taking some diphenhydramine (by way of benadryl 25mg gelcaps), about a 300mg dose. However SWIM began to wonder if this was a wise decision as SWIM had a dental appointment tomorrow to have SWIM's wisdom teeth removed. For this proceedure, SWIM would be put under by way of some substance that SWIM cannot recall at the moment.

So, SWIM was wondering, would there be any risk by dosing now, at 3:35 AM, if SWIM had that appointment tomorrow at noonish?