Thanks for writing in.
Monistat is known to cause side effects like itching, irritation but at local site i.e vaginal area. Similar side effects on face is unlikely.
One of reason for this could be either you have touched facial skin after application. If you have excluded other causes of reaction as mentioned above, other cause could be systemic reaction to drug after absorption of drug in to blood.
The form of reaction differs as per indivisuals, so having come across similar effects is unlikely.
I would recommend you to stop drug, if reaction is very severe and not tolerable.
lotion on face for soothing effect. Anti-histaminics like cetrizine
also help to relieve symptoms.
I hope I have answered your query. In case of any doubt, revert back for clarification.