I don't know where you live and whether you do or don't have a lot of options for ophthalmologists, but I recommend changing doctors. Immediately. You shouldn't have to suffer because your doctor doesn't understand the issue. So many stupid doctors out there!!

You're right about how they come out at night to mate and lay eggs. D. Brevis are what has clogged up my Meibomian gland (and probably yours, too). They're also found on the neck and chest. From a 2014 article I just found in the NCBI titled - Human Demodex Mite: The Versatile Mite of Dermatological Importance - I saw this:
"Female Demodex are somewhat shorter and rounder than males. Both male and female Demodex mites have a genital opening and fertilization is internal. Mating takes place in the follicle opening and eggs are laid inside the hair follicles or sebaceous glands. The six-legged larvae hatch after 3-4 days, and the larvae develop into adults in about 7 days. It has a 14-day life cycle[6] [Figure 2]. The total lifespan of a Demodex mite is several weeks. The dead mites decompose inside the hair follicles or sebaceous glands." Lovely.

It's a really good article, despite it being 10 years old. One of the things they say is:
"Pathogenesis of demodicosis and immune response to mite invasion are poorly understood.[31,32] Many views have been put forth..." That's an understatement.

I needed Xdemvy because I had (have?) a "Demodex infestation" and this is what has been shown to kill them after six weeks. I rescheduled my cataract surgery three times because of the dry-eye because it could impact the measurements for the new lenses. I wasn't told about the infestation the surgeon sent me to the dry-eye specialist I had been seeing before changing practices. Once I learned about the mites I cancelled again and rescheduled for 4/2.

Do you get any crusting around your eyes or eyelashes? I did; they're called collarettes and is one of the ways it's diagnosed.

Did you order the tiny brush? I hated it at first but now I use it twice a day dry and wet (only one eye gets it dry because the brush gets wet when I rinse it before using it on the other eye -don't want any transference!). I got an email from CVS today reminding me it's time for a refill (I thought they would be dead!!), so I went online to my account to see how much it would be and they say it's around $750. I plan to call to see why it was so much more last month. (I might have an out-of-pocket to meet first). Tarsus is supposed to have a program for getting it for less, but I haven't found it yet. And time was running out with the 4/2 surgery looming so I paid it.

The video from Tarsus, the Xdemvy pharmaceutical company, is on their website:
tarsusrx.com/demodex-blepharitis/ (this Mayo support site doesn't allow URL's), but type that in with https:// in front of it and scroll down to the video.

For the erythromycin, it does get in my eyes but it's not a problem since I do it while I'm already in bed and won't be bumping into anything. It doesn't sting at all. Two doctors who prescribed it didn't tell me how to put it in, but I figured it out once I knew what the problem is. Here's what I do:

I put a wad on my finger and rub it over my entire eyelid up to my eyebrow (where I put Vaseline); then I get another wad, pull down my lower lid and put it there before getting more and rubbing that onto the lower lid and then the upper lid (with more), then I get more and put it INTO the inside and outside of lashes at the bottom margins. It's a tiny tube and I have multiple refills so I slather it on. I make sure I'm not doing anything else and then go to sleep. Oh, I try to change fingers for each eye or wipe my finger clean. In the morning I have those round cotton pads and Micellar water next to the bed, and before I'm out of bed wipe each eye several times with a new pad for each wipe. Then I put my drops in, do the Wordle (compete against my husband), watch the Today Show, get up and change my pillow cases.

I'm hoping this is the only time I'll use it, but if I need it again I'm hoping it'll be covered by Medicare or cost just $50 (still a lot, but it's not $997!). But that's what I read could be for 2025.

Where do you live?