Swollen paw between toe

Hi, my dogs paw in between the toe is constantly swelling so badly then it will go down again then swell again. Does any one have an idea what this it? It was squeezed about a month ago and a small bit of grass seed popped out and we thought that was the problem bur could there still be some in there? thank you 

Hello - yes, foreign bodies often fragment within the tissues and if one foreign body has come out, a second one is certainly possible.  Other underlying prognoses may also exist so it may be worth chatting to your vet to come up with a good plan from here.