Forehead Thermometer Digital Infrared Body Temporal Thermometer Temperature Measurement Tool for Fever, for Kids, Children, Adults, Infants, Toddlers 89.6℉~109.2℉ (32℃～42.9℃)

I am having difficulty using this thermometer. It does not stay set at Fahrenheit.It flips back to Celsius. I also keep having the number 25 flashing on bottom of screen. I have tried to trouble shoot on the web with no luck.