I know exactly what you're talking about! I've tried to explain it to a few family members and friends but they didn't understand. It's nice to know that this happens to others with Lyme.
For me, this has been a MAJOR problem. It seems that it happens if my internal body temperature is not in sync with my environment. I have, however, been able to manage it more successfully recently (thank god!). It definitely is embarassing to look like you have an itchy sunburn right after you go outside. I have learned that NOT MATTER WHAT, DO NOT USE LOTION WHEN THIS HAPPENS! I put sunscreen formulated for babies on while I am inside and wait to step outside for at least a few minutes.
Wash your hands in cool water (not freezing, but try not to use the hot water).
If it is warm/hot outside, cool the car off before you get in if you can.
Drink cold (ice) water before you get in the shower! Also, turn the water on a low-warmish temperature and let the bathroom moisten a litte before you get in. I've found that the more regulated your body is with the outside environment, the less the red patches come. Although it may be tempting to take a nice hot shower some days, it's not the safest idea (I have found that if you drink tea or coffee before a hot shower that helps too).
In the shower, try to match the water to your body temperature (it's amazing how often you have to turn that thing!). Towards the end of the shower, turn it as cold as you can comfortably stand it. As you adjust, turn it lower. The red patches should be lessening. I turn it colder about 6 times before I turn the shower off. It's amazing! I used to turn off the shower and feel all itchy and feel like the heat was suffocating me. Now, I just pat myself dry (rubbing makes it red and burn) and put on deodorant (I've learned that it's best to wash my face at the beginning of the shower and not put anything on it after that).
Put on facial sunscreen (or any) AFTER you have cooled off from a shower and such!
Drink cold liquids and try not to itch. The other day, I went outside and soon my entire body was burning. I drank ice water and didn't itch (or even move, really) until it went away. I was freezing for a few minutes after that, but it worked!
I tried to wash my face after dinner last night. Afterwards, I found out that it is possible to melt a bowl of ice with your face!
Take your socks off while cleaning (I'm not sure why, I think maybe it's friction).
When you do get unbearable red patches, put a cold drink, an ice cube, or anything of the like at the time on that spot (but not so long that it hurts; cool it, move it elsewhere, and come back later!<3).
If you are going outside where it is warm, drink something to warm you up first (like coffee) before you step outside so your body can adjust more easily (but make sure to have cool drinks on hand if you have to be outside for a long time).
For some reason, I think I start to flush more when I have to pee... be right back.
When I think of more suggestions, I'll be back!
I really hope I help (THIS ITCHY STUFF SUCKS!).
I'm actually itchy right now. I need some water.