First there is no such thing as "chemical free" products. Everything is made of chemicals you are, I am, the computer I'm writing this on, the food we eat and the air we breath everything is made of chemicals.
Second natural and harmless are not equal. Cobra venom is natural as is the flu virus and the bubonic plague but they are not harmless.
From a single exposure I would not worry about it but don't get it done again.