I don't pretend to be an expert on this, but if it is spider mites (and by
the look of it, it could be), it is treatable. You can mix 2 TB. vegetable
oil and 2 TB mild liquid soap (not the degreasing type) with a gallon of
water and spray, especially the undersides of the leaves. Repeat as needed.
Do you see any webs at all?

Diana