Hi.. Welcome to HEALTHCARE MAGIC.. I have gone through your query and can understand your concerns.. As per your complain it seems that ringing in ears can occur due to causes like ear infection, perforated eardrum, excess ear wax accumulation, Eustachian tube dysfunction, Meniere s disease, TMJ disorders, Acoustic Neuroma etc. As your son has got slapped over the ear, perforation of the eardrum might have occurred due to sudden blow and it has led to ringing in ears.. I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like Audiometry, x Ray MRI can help in diagnosis and treatment can be done accordingly.. In case if there is perforation in the eardrum you can be advised antibiotics, anti inflammatroy painkiller and nasal decongestant sprays.. Antibiotic eardrops can also be advised.. In case if ringing does not resolve then you can be advised medicines like Tricyclic Anti-depressant like Amitryptiline, anti anxiety medication like Alprazolam, as well as Multivitamin supplements can be advised.. White noise devices can be advised.. You can also be advised Neuromodulation.. Avoid exposure to very loud sounds and also avoid diving, swimming etc.. Hope this information helps.. Thanks and regards. Dr.Honey Nandwani Arora.