Confusion regarding Dog bite. Or not.

4days ago a small accident occurred while I was riding my bike. I somehow controlled the bike  a little bit but  could not balance it and fell down slightly(a very very minor accident). At that time a barking dog came near me. After some time I realised there were little scratches in my leg. As All happened within a fraction of second, I could not know whether that scratches were because of dog bite or because of felling down. After that I went to the hospital and the doctor told that she could not recognise whether it is a dog bite or accidental injury by seeing the wound. She also told me to take the injections(0,3,7,20th day) . I took a Tetanus on that day and an injection on the very next day(0thay). Today is the 3 rd day but I did not take injection. Is there any problem if I take injection tomorrow. Here I attach images of my leg. Please tell me whether it is a dog bite or not.