Boston Butt should be cooked to a minimum internal temperature of 190°F which means it's cooked and safe to eat.
Some other cuts of pork can be done when the internal temperature reaches 145 F but cuts of pork like Boston Butt needs to be cooked to higher temperatures.
As long as the internal temperature of the Boston Butt meat reaches 190 F to 200 F it's cooked.
If you notice it doesn't look cooked fully then cook it some more until it does.
Boston Butt can take between 8 to 10 hours to cook in the oven at 250 F to 350 F degrees.
In the smoker Boston Butt can take between 8 to 12 hours in the smoker depending on how you like it done.