I noticed a head louse on my daughters head and had a bottle of Hedrin Treat & Go in the cupboard so I’ve used it on her hair. I just looked at the bottle and the use by date is December 2019! Should I rinse it off? Posting for traffic really as I was planning on leaving it overnight but will have to stick her back in the bath. I’ve googled and can’t find any info on it. It’s not chemical based more of an oil that suffocates the head lice.