Just take the loss. In the long run you can look for opportunities to make up for the shame.
I mean I'm sure there are some great try-hard micro tricks out there, but unless you can muster allies and avoid getting stackwiped and avoid losing your territory, you should take as close to a white peace as you can take IMO.
(I was playing an Ironman daimyo->Japan game yesterday, Korea sicced Ming on me--I quickly lost my outnumbered fleet--I took out ten loans, raised an 40-stack which was above my FL, had +2 mil tech on Ming, and despite trying to defeat in detail I just got stackwiped in my own soil by sheer numbers--took out another set of loans, raised another 40-stack, stackwiped again; I had to take a 95% warscore loss--I'd have RQ'd if I didn't have Siberians/Ainu to release to buffer much of it)