50/50 peroxide & water on hair transplant recipient area on day 5 for crusts. Did I doom my procedure?

It is best to follow your doctor's advice over advice from the Internet. Unless the advice is to follow your doctor's advice. In general you should not use peroxide. See your doctor for a recheck.

I do not recommend using peroxide on healing tissue after having a hair transplant.  It is unlikely that you have caused damage. 

I think dilution of peroxide is very dense and may harm to grafts . But after 5 days of hair transplant, grafts start to have vascularisation in skin and they are nor so vulnarable any more . You shouldbetter to visit your doctor.

has been shown to be bad for healing. However, this can vary by size of wound and time after wound. You should follow your doctors instructions for best chance of results.

The best way to treat crusts is to prevent them from forming. Within 3 days of surgery, you can resume full
activities, heavy exercises if you wish. The recipient area requires daily
washes as well to keep the recipient area free of crusts. I generally recommend
the use of a sponge and supply my patient with a surgical sponge to fill with
soapy water and press on the recipient area daily. By repeating this daily, all
crusts can be washed off without any fear of losing grafts. IF any crust are
present, use a Q tip and dip it into soapy water, and roll it on the crusts and
that will lift them off without dislodging them, but never rub them, just roll
the Q tip on the recipient crust. I like to see no evidence of any crusting in
the recipient area and the crusts from the donor area gone in 7-10 days with
daily washing