My son has been given eardrops with perforated eardrum. how do eardrops heal the perforation?

Drops help: Kids will generally perforate the ear drum with some forms of middle ear infection or occasionally trauma. The drops can get thru the hole directly into the middle ear & kill off germs like a weed spray, bypassing the need to take oral meds.The ear drum itself will gradually heal the hole as long as there are no germs & pressure interfering with the process.