Haven't you had a foot check since you've been diagnosed?
My DN always checks between my toes. I should tell your DN about it, then you should be given some treatment.
The best cream I've used is as a product called galpharm athletes foot cream, I can't remember if I got this on prescription or over the counter but it's by far the best having tried lamisil and other products.
Mine tends to come and go, I've not been troubled for a year or more but it is a condition that never goes away, bathing daily and drying between the toes is good advice as well as letting the air at your feet when resting on a night-time.