i have been on fent for 10 years or more fibro arthritis bad disk spynal stenoses or however its spelled and lots more it helps to have the area shaved very clean and slap and rub the area a few like a druggie does then if emergency i use my wifes diabetic needle shooter but that taks away from how many days it works you might want to increase to 50 25 is low and dont do crap for me