The definition of a barrier to immersion (chatzitzah) is based not only on the individual woman but also on the practice of women in general. Despite the fact that you never remove the ring, the general practice is to remove all jewelry prior to immersion. If you never remove it and there is a reason that you cannot do so, please get back to us with more information.

If the problem is that the ring is hard to remove, but loose enough to rotate, then you could wet it in the mikveh prior to immersion, twist it a few times to assure the water has gotten underneath, and then immerse. (If this is the case, it may be helpful to discuss it with the mikveh attendant beforehand so she understands that you already asked about this and were told it was ok.)