There are a couple of possibilities. It is unlikely that my bed "has ticks" unlike fleas and bedbugs, ticks don't come inside on purpose. Also, I had just put freshly laundered sheets, straight from the dryer on the bed. It is slightly more likely that I missed it when I did my evening shower and tick-check, and it crawled from someplace else on me, however the most likely introduction is the cat that sleeps with me. He was dosed with frontline 2 weeks ago, so it is possible that one got on and jumped off for sweeter meat.