What happens when you don't take enough SN or end up being found after a proper dose? What are the potential damages?
I can't say for certain what are the potential damages because individual cases differ. Some people recover without any sequelae while others do get issues. There is a hypoxic brain injury but to what extent in any particular case of sodium nitrite is something I can't say for sure since only two cases I've seen that reported extensive hypoxic brain injury did go on to be declared brain dead so they died. Other factors could be whatever current issues you have that may affect the respiratory system that could exacerbate toxicity.
Not enough SN means that your body may convert it back to Hemoglobin by itself although it'd be best to go to the hospital to get anything checked out. There have been cases where people do not finish their sn drink, vomit all over the place but end up relatively ok because whatever was remaining in their system was coverted back to hemoglobin.
being found after taking a proper dose could end up one of two ways.
1. The facility you end up at could not have any methelyne blue in order and since placing you on oxygen is useless after getting past around 30% Methomoglobin levels then if they can't get Methelyne blue in time then you are most likely going to die because alternative treatments aren't as effective as converting the Methomoglobin back to Hemoglobin
2. You could already be dead by the time you are found. Sn poisoning works fast and since it is still relatively rare, unless they know what you took then you aren't going to survive.
If you have the chance to look at the different cases of failed sn experiences then you should get a better idea of what will happen.