As I rather expected, the nice doctor at PAMF Urgent Care -- she remembered me from a previous visit some years ago, which is remarkable to me -- said that I have a broken blood vessel in my eye, that it's minor -- like a bruise -- and that aside from not looking very nice, is not anything to worry about. It should heal in 1-3 weeks. So those of you who see me at Worldcon, try not to worry about the nasty red spot in the lower right corner of my right eye. She did suggest that the fact that I'd ramped up my aspirin intake because of my back pain might have made my blood slightly harder to clot, and that's why the spot spread as much as it did, so at her suggestion I'm cutting back the aspirin to my normal maintenance dose and using ibuprofen for the second dose of painkiller I've been taking in the mornings.
My thanks to everyone who posted messages of sympathy and support. It's good to have friends who care about you.
Oh, and I did try the alternative route around downtown Palo Alto, and while it worked, having to make two unprotected left turns (on to and off of Alma) during heavy traffic times is almost as bad as having to swim through the heavy tide of University Avenue traffic. And, wouldn't you know it, I got a phone call, and this was one of the few times I'd forgotten to put on my headset, so by the time I was able to get pulled over to legally answer it, it had gone to voice mail. No really big deal, but it's one of those "it figures" things.