Did you test a pc of stone before you put the enhancer on your back splash? Did you read the label on the product container?
Enhancer doesn't give the stone a "wet" look, it brings out the colours in the stone and may darken the overall stone colour. It will also change your grout colour. Enhancers are non reversible. Once there on, no changes can be done.
Sorry to say, your stuck with the look you have now. It's almost impossible to get any other product to absorb into the stone now.
And I personally would not use mineral oil.
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Randall