Scar tissue or regrowth?

I am 36 years old and a year ago had been going to the doctor for back pain. While getting an MRI to find out the cause of the back pain I was told that they had found a tumor on my liver the size of a softball. I went through all the proper testing before I had a liver resection done to remove the tumor. The liver resection was done in July of last year. Recently I have noticed that there is a bulge coming from where the tumor was removed. I am worried that the tumor has started to regrow its self. Is that possible?