I'm on allegra 180mg in the morning, xyzal (levocetirizine) 5mg at night, plus dymista and immun shots, and i still get a lot of white mucus when i do a sinus rinse why?

Some mucus is normal: Your therapies are to control symptoms, but your upper respiratory mucosa is still functional. If sneezing, congestion, runny nose, etc are controlled then i would not be overly concerned with the nasal wash results.

Mucus: A medication regimen of oral antihistamines, nasal steroid/nasal antihistamine and allergen immunotherapy should be very effective for treatment of allergies. If there continues to be a lot of nasal mucus, other possibilities include chronic sinusitis or irritant rhinitis.