I have an antique silver coin that I was planning on displaying on a ring, and I was wondering if there was a protective paint that I could put on the coin. The paint needs to be scratch resistant, protect the coin from water and oils, and needs to be able to be removed from the coin without damaging the coins value. I do not need the paint to protect the coin from tarnishing just to protect the coin from normal wear. I haven't been able to find anything myself and I am not a coin expert so I was hoping a coin expert could help me with this, thank you.
It is unclear from your question whether you want to protect the coin from tarnish or whether you want to protect it from scratches and dings.
If the former, the comment of @Simon B is right on. Antique silver coins that have numismatic value (more valuable than their metal content) should never be polished to a silvery gleam if you want to retain their value. They can, however, be cleaned of dirt and grime and there are articles on the internet telling you how to do this safely and effectively without affecting their value. None of these methods involves a protective finish.
If you want the coin to have the gleam of silver, even though it may lessen its value, then just polish it periodically. There is no point being fanatic about a coin whose value is only in its silver content (plus sentimental value) and does not have any numismatic value. Incidentally, the term for tarnish on an antique coin is called patina, and is highly desirable. There are even articles on how to introduce patina onto the surface of silver jewelry.
If, on the other hand, you want to protect the coin from dings and scratches, then you should:
treat the ring like a pearl, opal, jade or emerald ring and not wear it when doing work on hard surfaces (e.g., gardening or repairing the car) or with tools; and/or
design the setting so that the coin does not project much above the setting. This can be done and still have a setting that shows off the coin to advantage.
I have several ancient Greek and Roman silver coins and the patina of 2,000 years adds to their beauty. If one of them got dirty, I'd clean it gently with a gentle, non-gritty soap, a baby toothbrush and maybe a Q-tip.