Speaking as someone who dealt with hard flaccid a couple times in my 11 years of PE, you just need to relax buddy and I’ll explain you why.
Hard flaccid is a condition that comes from extreme amount of unwanted stimulation from your penis, simple as that.
As a response to this, your pelvic floor tight up very hard in an attempt to tell you "let me rest a lot please", and of course your prostate suffers from this condition too causing usually to pee very often during the day.
Now you might ask, how do I heal? Leave it the fuck alone, forget about it first.
Then there a couple of things you should do which is eating pineapples or purchasing a simple pain killer with bromeline in it (comes from pineapples, nothing heavy don’t worry).
If you find yourself very horny during your recovery time and you have a spontaneous erection you should 100% masturbate it will help relax your pelvic floor, ONLY if you had a spontaneous one.
And of course have sex if you can, if you have a stable partner communicate your issue and obviously sex is probably not gonna be great because let’s be honest sex with an hard flaccid is extremely hard (it was for me at least) and size and EQ suffers a lot, but if you and your partner want to have sex that will speed up your healing process massively.
Other than these 3 things you can’t do absolutely nothing, but don’t stress, you WILL heal if you stop caring about him and start taking care of him. Keep in mind that hard flaccid is a long lasting injury and for me personally it took almost 2 months to fully heal every time I got it.
Wish you a speedy recovery and again forget about it.