What Causes Chills In Body Along With Dizziness?

Hey sorry for asking but year and half ago I got in a severe motorcycle accident my head went right I to a barrier but after being out for month started smoking weed and drinking again was wondering if it has long term afte ta or if it s natural seems like when we my. Key gets hot I feel all dizzy but right when I get freezing cold my dizziness goes away what should I do to help heal or if that s a natural things that time does to people with severe head injurys