Hello, Thank you for asking your query at DoctorSpring

Yes, there is no problem in using a 5 % Permethrin, in fact its more effective than 1% Permethrin. I suggest you to read the package directions carefully before using the medicine.and follow these steps:

1. First, wash the skin properly with mild soap and pat it dry.
2. Take the cream and massage it into the skin throughout the body. I suggest you also apply on soles and don't forget the underarms, groins and creases in the skin. Though it very rarely affects the scalp, its better you apply the cream on hairline, forehead and side of head
3. Leave the cream on your skin for the entire night and wash it off the next day morning. Wear clean clothes after your bath.
4. Itching might continue for a month even after treatment has ended. This is normal and nothing to worry about.

Hope this helps. Please feel free to ask follow-up questions.