A few weeks ago while I was swimming, a wave crashed into my left ear and it felt like there was water in my ear. Later, that day while I was cleaning my nose, I realized air goes out. It can hear as well as my other ear, but when I use headphones it has no sensitivity to bass sounds. My question is, can my ear repair itself? Or should I have a small surgery? Are there any other options?
Perforated eardrums (or ruptured tympanic membranes) are a problem older than mankind. The majority of cases (reported/observed, ~80%) heal spontaneously with little residual hearing loss or other problems, usually in a few weeks.
It is acceptable practice, therefore, to only observe traumatic TM perforations for healing.
If you are still experiencing hearing loss, however, you should see an ear specialist (ear, nose and throat if in the US). They will determine if your hearing loss is due to a chronic perforation (one that has not healed itself), or middle-ear bone damage (or another possible cause) which occurred during the traumatic event. In most cases, there are surgical treatments. If the perforation is still present, a simple patch may be all that's needed. If a bone was injured, the surgery (bone repair or replacement) is more involved. Other injuries are treated dependent on case.
Edited to add: During healing, care should be taken to keep water out of the ear (no swimming; baths or showers with protection from water in ear), and, though I have not seen a study on it, I would recommend against headphones except at a very low volume. The healing membrane isn't as tough as the original.
Traumatic tympanic membrane perforations: complications and management.
A prospective study evaluating spontaneous healing of aetiology, size and type-different groups of traumatic tympanic membrane perforation.
Tympanic membrane perforation
Early paper patching versus observation in patients with traumatic eardrum perforations: comparisons of anatomical and functional outcomes.
Spontaneous healing of traumatic eardrum perforation: outward epithelial cell migration and clinical outcome. Lou ZC1.