Are there risks?

Hey, getting out of bed in the morning is a risk. Having an orgasm is a risk (you could alays have a heart attack, right?).

The biggest risk in penis enlargement is overdoing it.

Oh yeah baby oh yeah
Because stretching and squeezing your penis feels good, penis enlargement can stimulate you sexually. Men have a long history of being stupid when the blood that should be in their brain goes into their dick instead. When doing penis enlargement routines, ask yourself, "Does this feel good?" If the answer is yes, you're on the right track. Then ask yourself, "Does this feel REALLY REALLY good?" If the answer is yes again, you may be getting distracted by sexual urges, which can lead to trouble. Some soreness is accceptable in PE, but pain is not.
I want a big dick NOW!
Sorry, fella, you ain't gonna get it. You will get in trouble if you apply too much force, especially in the beginning. Be patient. Some people get results quickly, some don't. I can't tell you what results to expect, but I can tell you that NO gains come to those who don't try! Keep a record of time spent each day, and what you did. It doesn't need to be fancy.