Mouthwash sometimes gives irritation to the gums and throat if the alcohol content in it is too high or if your gums are too sensitive. You can change to a more natural mouth wash.
Always use your mouth in 1:1 ratio. Dilute it in water before using.
Next Steps
consult your dentist about it to change your mouth wash.
Health Tips
Do not eat anything spicy or too hot. you can avoid using mouthwash for sometime till your condition heals and try using warm water and salt. Then you can change to a natural mouthwash.