Hi. In my opinion you must have your eardrum looked at by an ENT specialist or your primary physician. It is a possibility that the impact of your injury may have injured your eardrum or the structures in the middle ear. A hearing test will be indicated as well. The echo and muffled sounds can be due to bleeding within the middle ear or ear drum tear or displacement of the bony ossicles in the middle ear. A hearing loss of 15-25 % may indicate drum or canal wall injury and a hearing loss of 25-45% may indicate ossicle injury or blood in middle ear. The ringing in the ear is from some damage reaching the auditory nerve causing it to misfire these sound signals. A hearing test will show high frequency hearing loss if this nerve is affected. No dizziness means rest of the inner ear seems to be alright. In any of the above conditions it may take anywhere between 2 days to 6 week for you to get your hearing back depending on what structure has been damaged. It is recommended that you keep your ear dry and prevent entry of water in your ear and do not try to clean the ear with ear buds or anything similar. See an ENT to have this evaluated in detail. Let me know if you have any other questions.