Toothache has returned 6 months after it first appeared, what do you suggest?

Have it evaluated: I suggest you make an appointment with a local dentist, or the dentist who restored it six months ago, if that was the case. Your post give very little info to go on, so that's why it's best for you to have it looked at. Dental problems only get worse and more expensive over time, and pain is not the indication of how broken down the tooth is.

Another look: Another look at the tooth is needed to see why the pain is there again. It can sometimes be hard to determine where the pain is coming from, but in time it will be found.

See a dentist: Unfortunately a tooth can heal itself and you will best serve yourself by a visit to the dentist. Your toothache can be temporarily treated with medication, but only the symptoms...ultimately you'll need to see the dentist for complete and permanent relief! Don't be afraid, modern dentistry is painless and amazing!

It's very simple: See a dentist to determine the cause of the tooth ache and the possible treatment options.