bite on lege, something from the dogs?

I got bitten last sunday last, now I had been sitting out in the garden in the afternoon, but it was only in the evening the back of my leg (lower) started to itch me, now I was around dogs, today is thursday and it is no better in fact very red and painful, I went to the dr and she gave me a tetanus injection, antibiotics and hydrosone cream, and if no better to go back on monday, its hard and red and swollen, could i have got something from the dogs.