I had a fungus develop under my big toes because of my combat boots! The lady that does my nails told me to keep them really short, scrape out from under them and soak in Listerine (yep, the mouthwash-brown kind) twice a day!! It took almost 6 months of diligence, but my toes are finally pretty again and I am going for my first pedicure!!! So, CUT THE NAIL BACK, SCRAPE OUT FROM UNDER IT, SOAK FOR 5 MINUTES!!!! Keep them short!! I got the fungus because of my nail bumping up against my boots, warm sweaty environment and too long in my boots!! Sure glad I am retired finally!!!