It is normal for itching to persist for some time after treatment for lice, even after the lice are gone. This could be due to the treatment itself, residue from the lice, or your sensitivity. Changing temperatures could also be a factor. To help with the irritation, you can try using a gentle, fragrance-free shampoo for sensitive or dry scalp. You may also want to reduce the frequency of shampooing. If the itching continues, you could consider taking an antihistamine like Reactine to help alleviate the symptoms. If you have any chronic conditions or are taking other medications, it is advisable to consult with a pharmacist for personalized advice. Feel free to ask if you have any other questions.