Thanks for the information;
for all bumps & bruises I've always used an ointment called Arnica. It's homeopathic. Hylands is a really great brand. check out the natural food stores. good luck.
Not certain why dettol would do that, have you some anti biotic cream, put some on the injury ,if theres some infection there it will help and it may be a good idea to have it looked at by your Doctor, I think in time it will fade ..good luck .