It’s unlikely to be any malignancy as you have mentioned the swelling is getting settled on taking medications . ( better to share the name of medications you had )
As you have mentioned this swelling frequently in area behind your ear - mastoid area and associated with ear balance difficulties - (vertigo) it’s better you take an ENT consultation
Next Steps
ENT consultation for Vertigo and frequent swelling in mastoid region
Health Tips
No need to worry , get proper treatment . Unlikely to be malignancy.