a strand of the thread on top of the jeans and see if it blends in - if it does that is the one you can use. anyone can do these jean repairs but if i do it the way i do most things, sloppily and carelessly, that jeans is as good as not repaired . fixing holes in jeans for the finicky perfectionist...
the hem twice and press in place. secure the thread knot inside the folds as you begin stitching. start stitching the hemming stitches - slantingly taking one thread from the outer fabric and one thread from the fold; continue doing this till the whole hem is finished. if you do it right the hem finish...