Never new water could cause so much pain?

I’ve posted once already about a problem I’m having with hard water in my apartment. I basically have to limit my exposure to the water in order to avoid a deep aching, searing, intense pain. If I use the water directly to the anal area, then afterwards I immediately get pain. I have a bidet sprayer that I normally use, but can no longer use it here in the apartment. Lately, I’ve been carefully rinsing my butt in the kitchen sink. It’s the only sink I can climb up on. It seems that if I don’t get the water as directly to the anal area it helps to avoid pain. It’s not really an easy task to get up there.
I’ve been going back to my home town when I don’t have classes because this has become so bad. I’ve been going back the last several weeks now and it seems to go away almost immediately when I use the water there. Last night I made the mistake of using the bidet and the pain that ensued was really bad. Bad enough I had trouble eating and sleeping. I tried taking a sitz bath with some baby oil in the water and I put some Vaseline on the area without much relief. This cycle of being fine using the water at home, and then coming here and getting irritated has been going on for months.
I’ve been using Vaseline with some success. The problem is after a while it doesn’t work, also it causes other problems like itching.
I don’t know why I am having such an adverse reaction. It does seem like I need to find a balance between moisture and dryness. It feels like my skin gets stripped really badly just after a few washes.
This is driving me nuts because I had finals this week and still have 3 more next week. But the major issue is I have a year lease on this stupid apartment! I’m so frustrated and tired of dealing with this, last two nights I got barely any sleep.
Just feel that there are very few options at this point, short of connecting a water softener to take the hardness out of the water. I think what I’m experiencing is hard water dermatitis on my anus. In addition, I have a really hairy butt which I know is part of the problem sometimes, but what can I do? This is driving me crazy, I’m so tired of it. Everyone thinks I’m crazy and that it must be something wrong with me. My landlord was trying to suggest that maybe my own fecal matter was causing an infection. I have zero signs of infection. No bleeding or discharge. Just a dull throbbing pain, sometimes searing after using the water that lasts for hours until it dissipates.
If any of can relate or know of any way I can remedy this problem (compact water softeners/filters/ advice) please reply.

Also, I go to the bathroom 2-3 times a day, eat a healthy diet and I am very regular.