No thanks.

This is an expression to use when someone offers you something, but you don't want it. Depending on how you say it, "No thanks" can sound angry, cheerful, or anything in between.

If you'd like to be more formal, you can say "No thank you."

(one's) skin feels (adjective)

Feelings like "oily", "dry", "itchy", "sticky", etc. are felt in your skin. When you talk about these feelings, it's often better to say "My skin feels ___" instead of "I feel ___":

My skin feels kind of dry.

all (adjective)

In casual speech, putting "all" in front of an adjective can make it sound more negative. Use it to talk about things that you don't like or that annoy you. For example:

Don't get all impatient.

She likes to act all shy when you first meet her, but within ten minutes she'll be talking your ear off.

He gave me his old computer, but it's all old and crappy.

You can even make positive descriptions sound negative using "all":

Why are you being all nice to me today? Do you want something from me?

oily skin

Skin that is "oily" is shiny and sticky. Oily skin can be caused by products like sunscreen. It can also be caused by natural oils in your body.