Field treatment of solar damage
Freezing multiple lesions like this is not realistic to clear the damage, much of which may still be subclinical in the apparently normal looking skin. Consider a field treatment such as fluorouracil cream, imiquimod cream, Photodynamic therapy (PDT) or radiotherapy.
The latter is especially effective on males with bald scalps because it causes permanent hair loss. Fluorouracil is cheap but gives poorer long term clearing than imiquimod. PDT is expensive and painful compared to the others but gives good longer term clearing. Regular sunscreen use is imperative.