I hate to be the bearer of bad news, but installing the Messenger app isn’t going to place your privacy in any more risk than the already embarrassing photos and “woe is me” posts that you’re putting on Facebook yourself.
Any indicator that will outright tell if a person has blocked you will violate that person's privacy.
Well, not many people know this but there is actually an FAQ with regards to the matter of whether someone has blocked you on Whats App.
But since we are always inclined to be nice, we will bring it to your attention for your convenience.
However, I'm sure that you ask nicely, if you could work things out.
Have you experienced being blocked on Whats App or any messaging app?