If they're facing each other, yes they will blind each other.
If they can't see the actual IR led's they should be ok.
This is 100% the right answer, but a "newbee" might overlook exactly what looktall is saying.....
It's fine to have the other camera in the field of view of the "covering" camera. It has to be if you want complete coverage (every camera covered by at least one other camera). It just can't be pointed in such a way that the actual IR LEDs on the other camera are visible to the covering camera. For example, if they are both installed on the same outside wall pointing 45 degrees towards each other, they will be fine because you won't be able to see the physical IR LEDs of the other camera. If they are pointing directly at each other, then you will get IR blooms. Getting IR blooms doesn't mean the images are going to be completely unusable either. By dialing in manual exposure and making sure the IR bloom is not in line with an important element of the field of view, you can make it work. Ri22o post shows this.