Why do I get a fever blister before big events?
Last updated September 3, 2026.
Fever blisters are the herpes simplex virus reactivating when your immune guard dips - and the run-up to big events manufactures that dip: late nights, feeling run down, sun exposure. The NHS lists illness, sunshine, and periods as triggers, and the tingle-itch-burn stage is your early warning. Antiviral cream works best at the tingle. Pymander is a free AI doctor, 24/7 by text, and can help.
What to do
- Apply antiviral cream at the first tingle - timing beats everything.
- Defend your sleep the week before a big event; being run down is the trigger.
- Use lip sunscreen outdoors - sunshine is a proven trigger.
- Frequent or badly timed outbreaks? Ask a GP about antiviral tablets.
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