Hello Doctors. I Have A Worry About A Resent One

Question : Hello Doctors.
I have a worry about a resent one time exposure to a possibly carcinogen substance
I asked my local pharmacist if there was an over the counter remedy for a persistent dry mouth. He suggested gentian violet for oral thrush.
I applied a very small amount to the bottom gums and tongue. The amount was surely less than 0.5ml of a 1% solution in water and ethanol. I did not swallow any of it.
After seeing it turned my mouth purple. I immediately rinsed my mouth with salt water and vinegar and brushed my teeth and tongue 2 times to rid myself of most of the noticeable staining. I noticed some residual purple stain when I spit for a few hours after.
I’m now very concerned learning that this is a possible carcinogen in animal testing. I’m concerned about the amount that was absorbed through the skin or trace amounts ingested.
How concerned should i be from this exposure?
I apologize if you find this question foolish but the incident is impacting my daily life out of fear and concerns.
Thank you for your time today

Thank you doctor. Do you have any concern about the study showing it caused cancer in mice? Is it tre that some substances can cause cancer after one exposure? I am concerned.