You have tried everything! Dishwashing soap, oil, Vaseline, but you cannot remove this ring too small because now your finger is swollen and it is even more difficult to pass the ring. And before you go to the emergency room because your finger changes color, do these last 2 tests. This is what the nurses or doctors will do before cutting your ring.
1) Start by doing a test with Windex to lubricate your finger
No oil, no WD-40, nor dish soap, just Windex! Apparently Windex is perfect! If it still doesn't work, use the technique that hospitals use, you will find it in the 2nd video, under this one.
2) If Windex does not work, use dental floss, sewing thread, or silk ribbon and safety pin. The thread will compress your finger temporarily to allow the ring to pass. Watch the video to understand the technique.