If you have done surgery for oral cancer will you need another surger in future?

It depend on how much cancer material they had to remove and if there are chances of it spreading somewhere else in the same region, then they will have to return for more surgery. I work in the operating room and I see patients who have return for numerous operations due to the cancer cells spreading rapidly to different areas of the mouth or just to have stages of reconstructive face surgery after having oral cancer removed.

Just because you have had surgery once does not mean there will be a reoccurence-ever. I had oral cancer 12 years ago and since then there hasn't been a problem.

It only depends on if it comes back or not.
Most of the time when they do surgery they take out the primary tumor and a margin of normal tissue to ensure that it wont return. They may also do post op radiation to also make sure they have got the entire tumor.

If it returns they may have to do another surgery or they may choose a different treatment; again it depends on the location and if it has spread.