Sudden loud sound causes Hearing loss.
It may be Temporary , permanent noise induced hearing loss , associated with Tinnitus( different sounds in the affected ear)
Some times there will be Perforation in Ear drum also.
This results in decreased in hearing .
Next Steps
Meet an ENT surgeon , do the Audiometry for assessment of level of hearing.
Health Tips
Better avoid or use ear Plugs to prevent these kind of damages.