Fido itches constantly , I dont know why

!
He's always licking his paw, non stop!
I had to put a cone on him cause he JUST wanted to lick his paw, nothing else, I looked all over the paw and I didnt see nothing.
I was bathing him cause I thought there maybe were some sand stuck in his paw, I used very mild shampoo, few minutes ago i saw that he was red between two ''fingers''

then I saw that it was little bit wet on it (I just blowdried his paw very well, and all the body ofcaurse, so it wasnt wet from the bath), Its like a small red pimple or something, could this be some fungal or what?