Dizzy spells metallic taste in mouth

After a serious road traffic accident in 2006 have suffered with neurological symptoms ever since.
I go 'dizzy' randomly - could be asleep in bed or sat at my desk at work completely random, then suddenly I get horrific pain in my head like an immense pressure like I am inhaling water. My body temperature rockets, my face does red, my left hand goes numb, I feel sick & my mouth fills with saliva. This lasts for 2-5minutes and I can get several episodes a day (8 is the most I have experienced) for about 5-7days then I can be fine for weeks. When I have a spell of this I am left with an awful metallic taste in my mouth 24 7 for about 2 weeks, with this I cannot taste food very well and tea tastes disgusting .

Please any ideas or info would be so much appreciated.