Look into between his "toes". My sam came home from daycare and was licking a lot and i found interdigital cysts in there. There looked sorta like red warts. I brought him to the dr and they gave me meds for them and they went away. Good luck!
Could be allergy, could be something foreign in the paw, could be he's soothing himself from anxiety; a lick granuloma. Paddy used to do that and he had a HORRIBLE l/g years ago. Keep the spot clean with Witch Hazel and begin telling him "no lick" each time he begins, gently removing his head from doing so.
Be patient, be kind, be firm. But do not let him lick!
Thanks for the responses, i was able to get a second set of arms, he does have a raw spot in there, but now it's hard to tell if that's from licking all day.... i suspect he got something in there yesterday since theres a big outdoor play area.
It is incredibly frustrating having him continually licking at it, it's so grating! off to vets if he's still doing it tomorrow.