Sorry to be repetetive, but here's the answer to a similar question:
Once you've started painting, you can't really speed things up. Oil paints dry by oxidation, meaning oxygen must reach all the paint, including the bottom-most layers, for it to cure. A fan may help, or moving the piece to a dryer atmosphere, but using heat is not recommended since it will dry the top layer too fast & cause the paint to crack. Any product used on top of uncured oils, other than Retouch Varnish, will cause big problems later on.
If you haven't begun, you can use a fast-drying alkyd resin medium such as Liquin or Galkyd with your paint and that will help the paint dry in as little as 6 hours. But using this on top of still-wet paint will lead to cracking too.
Good luck with it!
30+ yrs an artist, 14 yrs selling artists materials