No risk of your personal hygiene contaminating your wort. Many people experience natural foreign objects of all sorts falling into the wort during the boil, not uncommon and it seems there's been no bad beer brewed because of it. You must sanitize everything that comes in contact with the wort after the boil.
If you have no other option then do a partial boil as BoisePorter said. I've done it many times, topped up with plain tap water though many would recommend boiling the water first. I think since there would be no hops in the top up water you would only need to get the water to 170* for 10-15 minutes which pasteurizes it.
Don't know a whole lot about doing wine but I believe there's no boiling going on there so you need to deal with the must differently than wort.