Does severe flaking occur after a hair loss procedure?

Hello. I've been hesitating about this for a long time, but lately I've been losing so much hair that I'm planning to get proper hair loss treatment at a dermatology clinic. However, after reading reviews that mention a temporary shedding phenomenon where more hair falls out in the early stages of treatment, I'm suddenly getting scared.

I am an office worker and have to go to work right away... I am wondering if getting a hair loss treatment will cause my scalp to turn red or flaky, making it very noticeable in my daily life.

I would appreciate it if you could let me know if I can wear a hat on the same day after receiving hair loss injections or laser treatment, and also how many days it usually takes for these irritation or side effects to subside!