Please help me rescue this carpet!

[ShutYerCakeHole]

We have a cream-ish, kind of bobbly, inexpensive carpet (inherited from previous owners so not sure what it's made of)
Recently used a Rug Doctor to freshen it up a bit, and have been left with a yellowish tide mark in some areas, where it look very obvious that it has been wet, if that makes sense.

DH also left a metal tin holding the door open while the carpet was wet, so now we have a lovely ring of rust!

Am on a tight budget and short on time, but can anything save it?

Try lemon juice and salt on the rust mark. Don't get it very wet though.

Is there underlay under the carpet? I wonder if there isn't and the marks are from the floorboards or whatever else is underneath.

Thanks wowfudge will certainly give that a try.

Not sure what's underneath the carpet, it does seem like the staining has been left by the Rug Doctor though, perhaps we didn't do it right!
Perhaps carpet shampoo and elbow grease is the way to go...

You may want to try this Carpet and Fabric Stain Removal