Hi & Welcome to HCM.
I appreciate your concern for your beloved son who is being bitten by your pet dog.
Your son must receive a total of 4-5 doses of
rabies vaccine.
Since he has already received one dose on May 20th (which should be counted as "Day 0"), he must take the next dose on days 3, 7, 14 and 28 as well.
Meanwhile your pet dog should be observed 10 days for the following signs and symptoms of rabies like biting without any provocation, eating abnormal items such as sticks, nails, feces, running for no apparent reason, hoarse barking and growling or inability to make a sound
excessive salivation or foaming at the angles of the mouth.
If your pet dog remains healthy and does not show up the signs and symptoms as described above the remaining doses of the vaccine can be stopped.
Hope to have answered your query.
A feed back is appreciated.