See an audiologist ASAP. This person will test your hearing and give you an idea of what's going on in each ear.
Then see an otologist/ENT straightaway. This person may be able to do something about it, depending on the kind of problem you have. However, he will need the information from the audiologist.
The issue could be a burst eardrum, dislocated middle ear bones, or several other things. Some can be addressed through noninvasive surgical procedures.
I'm so sorry this happened to you. Let us know how things go!
Thanks for your advice, i was trying to avoid the doctors as i've got my army selection for the paratroopers in 3 weeks and this is sure going to get me a lengthy deferral with it on my record. Is there any chance i can risk leaving it for 3 weeks? or does it need immediate attention? really appreciate your help, thank you.
It sounds like a concussion - minor will go away on its own... look up to see symptoms and treatment. On the other hand concussions can be serious.
I hope you filed a complaint with the police... it may help someone else from getting the same treatment. Doesn't sound like the UK to me. But, I haven't been in Europe at all in several years. I do recall the shock way back in about 1990 when a colleague was mugged in Geneva just a block two from the UN facilities. Up to that point I considered Geneva absolutely safe from such.
Back in the 90s I was 6' 6" and 250 pounds, and never had anyone threaten me. In the US size may not be enough.
You say paratrooper, so you must be a "tough" guy, seriously, I am a veteran of the US Navy and always hold the higher risk military in high regard, but nothing I was up to doing myself.