I smoked out of straight plastic and weed 4 years ago, could i have brain damage?

Possibly: It hard to tell.But we know that the use of drugs can lead to injury to the brain cells--ie. Brain damage.Obviously the degree of smoking and whatever else was used will affect the degree of brain damage. Its a good idea to avoid if you have concerns. Ultimately, you have to look at manifestations of brain damage-ie. Chronic headaches, trouble thinking, problems with memory or coordination.

Very hard to say: We can not answer this question, but there is no doubt that smoking weed out of plastic can be harmful, but it depends how often you did this and how long you did it.If it was only once or twice, it is less likely to cause brain damage but in any case consult your doctor and get yourself checked to see if you have any neurological effects(brain damage)from what you smoked.