Help please. could an air purifier be the perfect remedy to my nighttime allergies?

Not likely: Air purifiers (when appropriate for room size) may decrease airborne dander and mold. It does not work well for dust mite as mite particles too heavy and not airborne. Best approach is to identify the trigger so specific avoidance measures can be done. Good air purifiers are very expensive and do have benefit in right circumstance. Invest in proper diagnosis first.