Why would my oil light stay on if all oil levels are correct?
The sending unit is likely bad; replace it, per repair manual.
Why would the oil light on a 1997 Camry 4 cylinder stay on after oil and filter was changed and levels are all correct?
That depends on the levels, however with high levels of chlorine when the sun is shining, it can burn the skin. There would have to be extreme elevated levels for that to occur, but it is possible. The real problem would be getting it in your eyes. It's best to stay out of it, until levels have returned to normal range.