Opening a wound to drain?

2 of fought one healing well other due to massive coat and us not seeing all wounds ended up swelling majorly with infection and we even noticed a few maggots. We pray ther not on inside of wound because it started closing. Still major swelling and needing to know if maggots would be in the closed wound and of so how and what can we do to soften closed gashes to drain infection and rid maggots if in the closed wound. We hve no money for pet clinics or vets. Our dogs are our children and really need help with this. What can we do if anything ourselves?