Essential Oils For Dry Skin Using Different Essential Oils?

Using different essential oils? - essential oils for dry skin

Ok, so I wanted to make the lotions and oils for use, but I do not know how they work. I know some are good for oily skin, some dry, some itching and a little help with things better than others, etc. So my questions are ...:

1. Oils, which help relieve pain? (Cramps, pain, etc.)
2. Help What is the oil? Oils with itching, pain, etc. help? Is there somewhere a list that tells me what oil means what?
3. Are they all safe oils are mixed?
4. How do I know which oils are safe for some people? Di Rosa is good for dry skin, but harmful for sensitive skin? How do I know?

If there is a site that says all these things, please add the link!