It is important to use good, wild Oregano. The best for me has been from North American Herb & Spice Co. The cheapest place I've found it is Iherb, 60 capsules for $21. I have tried different brands and none of them were as effective. You can pierce a capsule and squeeze the oil out for external use or buy drops.
Oregano and Thyme are closely related so it probably wouldn't help to use both.
If you think Chamomile will be helpful why not make tea and spray it or splash it or rub it on with a cotton ball. It should be very soothing.
There are very strict guidelines to using Essential oils internally. Some of them are dangerous. Those that are safe must be purchased from reputable dealers so you know you are getting a quality product.
Essential oils used on the skin must be diluted in a carrier oil or even alcohol.