Sorry to hear about all your troubles. Sadly I know how it is, as I find many similarities to where I was 2-3 years back in time.
Based on my personal experience, you are in a negative spiral at the moment due to this extreme trauma that you are going through with hyperacusis + tinnitus. When in this hypervigilant fight or flight mode, anything and everything will feel like a threat - and you start believing that the ramping up will stay forever.
Speaking of my own experience, I'm pretty sure there is no permanent spiking due to your walks, as long as you try to stay away from exposure to loud noises at this stage.
Do you get any sleep? Are there sounds, at a low level, you feel somewhat comfortable around - to get some sort of auditory input?
I think you should try to implement some kind of sound input that is okay with you, on a high quality speakers. And implement some "tools" that may help you in calming down your nervous system.
Are there any specialists where you live in the field of hyperacusis + tinnitus that you can talk to?
Perhaps check out what
@Greg Sacramento mentioned too. If you suspect there could be some connection.