https://tibia.fandom.com/wiki/Adventurer%27s_Blessing
In here you can see the following part:
But beware! As soon as your character as first starts a PVP combat with another player (you need to deactivate your secure PVP option first - a red warning message will appear) or reaches level 21 for the first time, the blessing will be lost.
Assuming tibiawiki's information is 100% correct, the only possible conclusion is that you do not receive the blessing back!
.
- Why is it the only possible conclusion?
It says you will only lose the blessing when you reach level 21 for the first time, so, let's pretend that you would receive the blessing back, ok? So, you died and now you are level 20 with Adventurer's Blessing again, and then you level up to 21 again, but that's the 2nd time you reach level 21, and since you only lose the blessing in the first time, you would be blessed forever! And we know that doesn't happen... so, the only possible solution is that you do not receive the blessing again.