How bad is acid for you if I've only tried it once.?

LSD Effects. If you do not have any current symptoms, you are fortunate. Most of the symptoms are related to large doses, and repeated doses. A few have had "flashbacks" after taking one dose. The more you use and the larger the doses, more serious side effects and long term sequela can occur. Not worth the risk.
Dont worry. I would not be concerned about any long effects after a single use.