Sound and light sensitivity usually come from the same injury. A part of the brain filters sensory input so most does not make it to the conscious mind.

It is like your brain has internal sun glasses and ear plugs. That sensory filtering system uses a lot of brain processing power. A concussion can reduce the available brain processing power so there is less filtering. With less filtering, more sensory data, light and sound, gets through.

Over time, this over-stimulation from light, sound, smell, and tactile sensations can reduce a bit. For some, they get back to a more normal level and only struggle when things get to extremes.

I have lived with this in varying levels for 54 years, seriously for 18 years. I am much more tolerant now than I was 18 or 17 years ago but light and sound will eventually exhaust me if I push to endure it.

The most important thing for you to know is this. Every brain injury is different. Once you pass the 6 to 8 week time and still have PCS struggles, there is no data about recovery time lines. Sorry.