Hello from JustAnswer.
Could you attach a picture of the rash?
Thank you for the pictures.
Yes, this looks like you are reacting to the massage oil, which is a type of allergy. However, it does not look bad at this point, so the skin reaction is not serious.
The plane flight would not cause an allergy or sensitivity, but it is possible that a long plane flight can cause the skin to be more dehydrated than usual, so that any reaction is more symptomatic.
To help this resolve more quickly, it would be reasonable to take an oral antihistamine, and there are many of these available over the counter. It also can help to apply an over the counter hydrocortisone cream, although it is less practical to use topical treatment with a more diffuse reaction.
If I can provide any additional information, please let me know.
Any antihistamine would be fine, but the antihistamine that is usually most easily found is Benadryl/diphenhydramine. The cream is the hydrocortisone cream that I noted above.
Yes, for short periods of time, such as a week or so. We try to avoid long-term application of any steroid cream to the genitals.