I want to know, How to allow access to blocked site for specific ip in mikrotik?

for example, I blocked the "www.facebook.com" in mikrotik and now i want to give the access to 192.168.1.100 client . how i can do it?

thanks

depend how you blocked it.

if you did it in a firewall rule, you could something like this.
This will blocked forwarded all traffic to 10.11.12.13 for all others than 192.168.99.1

Or you add a separate rule above the blocking rule, where you allow access to the site.

I blocked the website by following the instructions, that mentioned below:

I blocked the website by following the instructions, that mentioned below:

It will block all packets that contains word http://www.facebook.com. For example a page with a link to it or linked image from it. Add more checkings, like: (PCRE compatible regexp)

If you have just found that your IP is banned you can get proxy account https://www.iwasel.com/en/ I was blocked, got the account.. connected with no degradation in speed... It's a great solution.