When I was home a couple of weeks ago my mom handed me a pair of jeans that she really looks good in but that were like 3 or 4 inches too long for her petite frame. She asked so nicely if I could pin them up to the correct length and then again so nicely if I could take them home with me because she worried that her sewing machine would severely balk at going through all that denim. So I did, cause I love her and I am a good daughter :)
So mom your jeans are hemmed and they look as good as new. The only difference you will see is on the inside of the hem. I don't own one of those special machines they use with twin needles and twin bobbins... I only have one bobbin thread to catch both top threads. But from the outside no one will ever know!