You don't need to freak out just yet. It sounds a bit different from what I and the others have experienced, so I think it may just be a strain. The Mayoclinic has some good information here:
http://www.mayoclinic.com/health/inguinal-hernia/DS00364
Wikipedia has some decent information and pictures of where it appears.
Where is it by the way and do you have a fever?
Some decades ago I had a bilateral inguinal hernia, which is basically two hernias: one on the left and one on the right. I had been doing leg lifts and was laying down on the weight bench instead of sitting up. Yes, it was a stupid thing to do. It hurt right away and there was a bulge that I could push back in. It hurt more and more as time went on, and after a few weeks it was difficult to stand up straight for any length of time. So, if it doesn't go away then you should have a doctor look at it. But, you don't have to immediately run out and get it fixed.
I think that you should take a break from crunches and leg lifts. If it's a strain you'll just aggravate it and still won't know the cause and if it's a hernia then you'll make it worse. If the pain lasts then I think you should have a doctor examine it. If it turns out to be a hernia then the doctor/surgeon can give you an idea on whether or not you need to have surgery soon or can wait.
In case you don't already know, the bulge is a symptom of a direct hernia. The small intestine breaks through the abdominal wall and fascia and pushes in between abdominal muscles. This is why you can sometimes temporarily push the bulge back in place. You should be able to push the bulge back in place with a small bit of pressure with one or two fingers. If you can't, and you haven't had it examined, then you should definitely have it examined at that point. There's also something called an "indirect" hernia. This is where the hernia pushes down and you might see a slight bulge between your body and the testicle. This kind of hernia is more likely to happen to runners.
I did have surgery on my hernias. If you have a hernia on just one side than recovery is not so bad because you can use the other side of your body to compensate. If you wind up having surgery I suggest that you get specific instructions about lifting and running after the surgery and follow them exactly. A few months after the surgery I was bailing out a flooded basement and ruptured it again (doubly stupid). The ruptures were smaller and this time I waited 2 years to get it fixed. Again, the point being that you don't need to freak out right away that it's a hernia.
Good luck and I hope it gets better.