ummmm one thing with the tea tree oil thing is it does work, but puppies and the majority of dogs will get chemical burns on their skin from tea tree oil, so it must be heavily diluted if used, and even then I wouldn't if they are already scratching.

Have you got capstar? Its a tablet which will help kill all the fleas within 3 hours. That with a spot on like advantage or frontline (but not one of the ones from the grocery store... they work for a few days) should do a good job, but if flea eggs are around they can still get fleas, they die within a few hours but they can still get them on unless you bomb your house & spray your garden.... sucks.

Have you actually seen the fleas? If you are still seeing fleas, definately go the capstar. Its incredibly safe and works amazingly well for outbreaks. If you aren't seeing the fleas, than it may be an allergic reaction to flea bites.... they need soothing stuff to help if thats the case. A high percentage of dogs actually are allergic to flea bites, which means even once you've dealt with the fleas, now you have to deal with allergic skin. Allergic skin is pink/red and can be hot to touch. Generally the big patches are above the tail and armpits.

If you aren't seeing fleas, and its an allergic situation no flea stuff will work. You can get stuff at the vet, but most of the time they want to give a cortisone injection and if the skin gets infected as it can from all the scratching they will want to give antibiotics instead. You can try some pure vit E lotion, or buy some leave on conditioner for dogs (remember puppy skin is extremely sensitive). Wash the pup and then apply the conditioner and that will help soothe. You can add fish oil or a raw egg for omega into their food to help boost the skins ability to cope as well....

HTH!