Ah, the dreaded deathsquito. Many have felt its sting before they were fully prepared. "Full metal" doesn't really say anything, do you mean bronze?

Then indeed, this will not help you at all. You need either at least the root chest (better), or at least a full iron armor (not as good) to somewhat take the, ahem, "sting" out of the deathsquitos bite.

And, of course, you always have to be fully fed with the best food your biome has to offer, or no armor in the world will help you.

If you landed in the middle of the plains area, with no easier biome close by, your chances of getting your stuff back are slim, but not nil.

What you need is a new karve, and a new outpost as close to the plains biome as you can get. It doesn't need much, just a fire, a workbench and a portal back home.

Pop through the portal fully naked with just one good weapon and fully fed. If you can run to the spot you died, do so. Otherwise you will have to risk another boat.

Once you got to the spot where you died, swing wildly at any skeeter who's trying to attack you. You gotta time it right, but when you hit them, they will die immediately. They don't have much health. I think a knife or dagger is the best, since it is very fast.

Grab your stuff and haul a** outta there as quick as you can! Preferably over land, because boat is initially slow and you can still be attacked by the deathsquito.

Oh, yeah. And avoid any of the other denizens of the plains. You really don't want to meet them right now. Try to give them a wide berth. You can outrun them, but Lox are VERY persistent and wreck anything in their path.

Good Luck and welcome to Valheim!