Answer
Temporary numbness and stinging are recognised local adverse reactions. Discuss persistent or troublesome symptoms with a pharmacist or prescriber.
Sources for this answer
- NHSNHS · NHS medicine guidance
- Benzydamine 0.15% w/v Mouthwash — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.