I've done acid many times before and I do get flashbacks, but thats a very misleading term. It happens when you recognize something that reminds you of a time when something extremely intense happened to you and it brings the same feeling back.

For example I spent an hour of my peak at a del taco and now whenever I drive past it I feel really anxious and lights start to become brighter and lights trail a little more than they normally do.

Its actually kinda fun.