I have bleached DHs shirt and now have a rust coloured stain on the collar

[MinkyBorage]

Any ideas how I remove it?
Also, does anyone have any idea why it has happened? I've never bleached his shirts before, and am thinking I'd better not bother again!

No idea,

But as matter of interest, why did you bleach them.??

Was there a tiny stain there already? Maybe blood from shaving or something? Chlorine bleach fixes iron based stains and makes them worse.you now need to get a rust stain remover,but it may be fixed into the fabric,sorry1

There may have been a stain there already. Thanks, I'll look for that stain remover.
Bree, they were looking a bit grotty, and normally he replaces them when they look like this, but I was trying to be thrifty. Can't work out whether it's environmentally worse to bleach a few shirts or to replace them