It might be unfair to say that all that remains of the past is memory. Unless you argue that scars are kind of memory too.
On a bad night, I find myself awake from pain because of running in a dream; running after an illusion. I have also experienced dream-like euphoria in which colors, smells and sounds become intense, perception of time distorts and my sense of self dissolves.
My memories toy with me and make me feel what I once felt, again and again, a virtual flashback. I’ve got more than enough memories of physical pain, of dysfunctional living, a reservoir to last with me for the rest of my life.