Giving tablets without cleaning maggot wound is risky. Tablets are decided based on animal age, body weight, and extent of damage. Once the tablet is given, the maggots will die. If we didn't clean it, then it would end up in toxicity. Hence, we need to check the dog and give tablets, and also, after that, cleaning is a must.

Pls take him to Veterinarian so that they will remove maggots and prescribe Medication..if you can't handle alone pls seek help of any NGO/Animal rescue volunteers in your area..

You'll have to seek professional help. Tablets aren't the solution here. You'll have to remove the maggots otherwise they will cause irreparable damage which is already too much as per you. The spray stated and it's alikes are very irritating so he ran away.