My pharmacist (my sister) recommends the use of sunscreen on my face. And to titrate the use of the lightbox (5 minutes the first day, 10 minutes the next if there is no reaction the first, 15 minutes the next if no reaction at 10 minutes, up to the prescribed dose of 20 minutes a day on the fourth day). The reaction is a skin reaction, a red and itchy reaction on the exposed skin. The lightbox needs to send its light to the eyes to have the necessary effect (the sensitive organ is the retina, not the skin) so that will work perfectly.

So that's that. Minimize the skin exposure while keeping the eye exposure as close as possible to the prescribed dosage.