One thing about lips is that you lick off the protection.

Some products are liposomal, enter into the skin and therefore last longer. I used to have one for the whole body that you were instructed to apply 3/4 of an hour before going into the sun. It was called daylong and was like an alcoholic solution. I don't think it exists anymore.

This product might help, the body version is very good
http://www.pharmacymix.com/product.aspx?ProductID=4687