Sounds like lyme. Even though he never goes outside if you do or another member of your family does then he could have gotten a tick. I had one the other day - we have an indoor kitten and I hadn't been out in the woods or yard that day but my kids had.
2 of my boys have had Lyme. Has he had a fever recently? That's another early symptom of lyme that's not well publicized. One DS had the bulls eye another had just the fever. The test is just a very simple blood test so i would see about having it done tomorrow. You should have results w/in 2 days.
It can show up 4 to 6 weeks later. Many people get tick bites and never know it until symptoms show up. Also, look for flu like symptoms, aching joints is another sign. Of course, you may not get ALL signs so OP even if he doesn't have any other he should still see a Doc ASAP.
ETA We are on symptom watch as per the doc for my ds. He was out in the woods last week and had a nasty tick bite on his scalp.
I'm the OP. Thanks to all of you for your concern, suggestions and information.
Something I noticed is that his "rash" is very defined, not shaded like most of the pictures I've seen. The red outer circle looks like it could have been drawn with a red pen as an outline. It is red-red, not pinkish red. I've told him he should get to the doctor to get it checked out and suggested we take a picture. I could tell he was paying attention.
We've been together for over 40 years and I know enough not the try to make him do anything. He'll make the right decision.
Thanks again
Can I ask you guys, if you had this bullseye rash about 2 years ago but didn't get it treated at the time (not realising what it was 'til this thread) is it worth getting tested for Lymes?
Octoberbride03 -- are you sure you removed the head and all? sometimes part of the tick can still be in the skin.
I thought there was a spider bite that could make a bullseye too. I googled it and it only showed ticks.