Veny, unfortunately there is nothing much I can tell you to do, there is only a few minute timeline that an open umbilicus can be sewn or stitched. I have seen people attempt to close them manually later with glue and stitches and they do well for a day or two and then they simply burst with infection. I am not quite sure what to tell you to do. if you have a cake of corn starch on it you can take the chance and pray that there is no bacteria inside and it will make it.
if you take it off, there really are no other options because more than likely its innards will slowly make way out again.