Hi,

as long as there is not much bleeding, the wound looks dry and no pus develops, DO NOT DO ANYTHING!
Above all, do not use any creams or other stuff-this could interfere with the healign process.
Phelsuma are adaptet to regrow autotomated skin quite quickly. In any case, the regrown scales will be smaller and more irregular than the original ones, but normally loosing even large parts of their skin is not a real problem.

Best regards

Ingo