Get Your Dog Care Questions Answered by Experts
Do you mean that the lump is back where the hernia was located?
I hate to say it because it's so late at night but you need to seek veterinary attention for this. If he is resting ok and doesn't seem to terribly bothered, you may be able to wait until tomorrow morning but, if you have an after hours clinic nearby, you may want to give them a call and ask if it can wait till tomorrow. As you know, this can quickly become very serious.
You can check for after hours clinics in your yellow pages.
Let me know if you still have questions.
Good luck! And let me know how it goes!