Ok, lets try not to freak this person out too much 
Yes it was not a good thing to put the new lizard without going through quarantine but what is done is done. This person said they were new to this and we have all made mistakes, as long as we learn from them it is ok. The thing to do now is limit the damage.
First step is to seperate them. In a pinch a cheap rubbermaid container of the correct size with good heat light and some hiding places will do.
Next is to sanitize the original cage. Empty it completely and wash down with a sanitizing agent. I use commercially bought but you can use a ten percent bleach solution. Just make sure to rinse with plenty of fresh chlorine free water several times and let air dry.
That is what you can do immediately. Next is to find a vet who deals with reptiles and get fecals done on both uros. Actually you may want to do the new one first then wait a few weeks to do the original one as some parasites take several weeks to show up.
Keep them seperated until you have a clean bill of health from the vet on both then you can finally introduce them together in the same tank and hope they get along. If they don't you will need to keep them seperately.
Everything will probably be fine. Most likely you will end up needing to deworm one or both of the uros. Since the new one appears to be healthy and robust it is not as likely that he has something really nasty, but you cannot be sure without a fecal exam.
Just don't forget quarantine next time as it is important for your lizards health and your pocket book (you only have to treat one lizard not several)
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Mike Wilson