I've delt with this condition for years,and yes it's treatable.
What you've described sounds like an interdigital neuroma. This is basicaly a pinched verve between the 3rd and 4th metatarsal heads. This can be aggravated by tight shoes or ski boots that don't allow enough room in the fore foot. The solution are varied.
1. Have a boot fitter stretch the boot in the fore foot are to allow for the spreading of the metatarsals.
2. Assuming there's enough room in the boot, start working on the footbed/orthotic. By using a cotton or foam pad that's roughly triangluar in shape that's placed behind the met. heads. This transfers the preasure off the ball of the foot back to the pad and again opens up the metatarsals.
3. Surgery. If it's a severe case that also happens with street shoes this may be a viable options. It involves an incision on the top of the foot at the affected area where the surgeon would remove the inflamed nerve.
My suggetion would be to find a competent boot fitter who's heard of this condition and has worked on other skiers with it, if one can't be found in your area, consult a podiatrists who is fmailar with sports medicine. Good luck.