Colour can camouflage the spot if you use a permanent marker or a fabric pen having same colour as that of your jeans. Before doing it, try making a test mark on the bleach spot to make sure that the colour blends. If nothing goes wrong, get done with colouring and leave till it dries up. You can find all colours of permanent markers available in the market. Just try to get a marker that closely matches the colour of your clothing that has been stained by bleach. Remember this only works for small sized stains and not big ones as you will end up with a large ugly permanent marker stain instead.
Make your jeans new and fashionable instead of putting it in the rack by using a suitable patch. The patch can be hand-stitched and may be name of your favorite band, cartoon character or perhaps a monogram of your first name. For more attraction shooting stars, pair of hearts or diamonds may be added. Although patches were popular some time ago, it seems anything retro is finding its way back on the social scene. Find some interesting patches that are big enough to cover the bleach stains and sew them on. You might find a good selection of interesting patches online at various websites.
Instead of covering up or hiding the spot, try giving it a Denim look using sandpaper. Applying a drop of bleach, rub it on the spot to give a real sandblasted look and doing the same to other spots on the jean. With the spot up the knee, go for full sandblasting moving up the pockets and seams. Wash thoroughly and dry till ready for wearing. Do not try this sandpaper technique unless you know what you are doing as there is a good chance that you can ruin your jeans further.