If it's sweat blowing upward from the face, I'd agree with Doc I. Try a few days growth of beard. Doesn't take much for the evaporative cooling effect. In winter I usually let mine grow out more but in summer I'll keep it shorter. Still works.

I noticed this years ago when I shaved my legs and arms for racing. It felt weird, clammy like my skin wasn't evaporating properly anymore. I don't have very hairy arms or legs and I notice it doesn't take much to feel more comfortable due to that evaporative effect.

There are also sun protection face masks of wicking fabric for active folks who don't want to wear sunscreen or need extra protection. An ultra thin bit of mesh wicking fabric might do the trick below the eyes without interfering with breathing. Or if you already have a bandanna or bit of thin cloth around, try it on one or two rides and see if it helps. I wear paper dust/surgical masks for rides on very cold dry days and it hasn't interfered with my breathing on moderate effort rides. And those masks don't wick very well -- when they get saturated with moisture from breath they tend to clog up and need to be replaced.

Same problem.
I also have a problem with the blind spot created by the top rim of my sunglasses. When I'm tucked down in the drops and look up at the road, I look up over the top edge of my sunglasses, and right under my focal point there's a blind spot created by the frame of the sunglasses. I wonder if some kind of helmet mounted lens would fix both of these problems.

I have found something that is definitely helpful, although I don't think I would call it 'a solution'.

I took a standard terrycloth washcloth and cut it into four pieces. Each piece is about the right size for 'eye wiping' and is much easier to handle than a full size washcloth. For me the standard washcloth held in my hand was always dangling over the mirror that I use (attached to my left dropbar) and the smaller one doesn't present this problem. Plus I really need a 'single width' of terrycloth to kind of force under my glasses without have to remove them. One quarter of a washcloth is about perfect. Since it is small I take a couple extras and change it every 30 to 45 minutes.

Not exactly a solution but it certainly is an improvement.

dave