4 main issues longer term.
1. recurrence of post herpetic neuralgia - this nerve pain may be disabling for flying duties for variable periods
2. The effect of pain medication for 1) on your flying clearance.
3. Note there is some evidence that a Herpes Zoster vaccination will boost your immunity and lower the rate of reactivation of the virus
4. In some immunosuppressed people it may indicate another underlying problem such as a haematological cancer, diabetes etc.