"Is this common?"
I am not a doctor but I use topicals frequently, interact with a lot of manufacturers and know a lot of other people who use them.
I have never heard of this but anything is possible. I wonder what is on the ingredient list and where you used the topical. Topicals when applied are meant for localized pain and do not enter the bloodstream so in theory they should not effect the body system as a whole. The topical penetrates or is absorbed into the skin barrier and interacts with CB1 receptors to help alleviate pain.
It could be you are sensitive to an ingredient within the topical. I too am suspicious when I try something new and end up with a headache. In the case of cannabis, I always make sure I buy brands that are lab tested and pesticide free.
This represents my opinion only. I hope this helps!
pamelahadfield
