If it was getting into the blood it should be doing about the same thing as pseudophedrine since they share a mechanism. You certainly shouldn't take either if they make you feel terrible though, and probably talk to your doctor about it. The way both medications are supposed to work is vasoconstriction, which could be a big problem if there is already high blood pressure for instance.
There's a lot of evidence out there showing no difference between phenylephrine and placebo, probably because of low bio-availability at low doses. One study below, there are many others:
https://www.annallergy.org/article/S1081-1206(10)60240-2/fulltext
Wow, what a dumb design. It actually looks less like it's braking with the brake lights on.
It's also got the whole brake light and turn signal are the same light thing I hate too. Just keep them separate lights with a yellow light for the turn signal.