Does a brain fog feeling after a second concussion go away, or does it stay? i only got it 6 months after my first one.

It is not feasible to provide a meaningful opinion without additional history, physical examination and may be some tests. It would be prudent to see a doctor, preferably a neurologist. Wish you good health!

Your post provides nonspecific data, but raises concern regarding a traumatic brain injury sequence. A neurologist would be helpful, but neuropsychological testing may be needed to objectify the extent of cognitive and emotional issues.