Rotte sick, need help ...

Dear friends,

I'm new in keeping dogs and need some advise here.

Recently aquire a 4 years old rottweiler from a friend to house it at my farm in lim chu kang.

Noticed it limps abit when it first arrives. Then last week was told by my worker that it doesn't walk anymore and eat and drink very little.Its both hind legs became very week.

Arranged and sent it to a Vet and was diagnosed with heart-worm.It was hospitalised for 2 days on drip and injection to cure this sickness.Medication oso provided.

Afterthat, was told to sent it home(the farm) and let it roam about.

However, it doesn't even walk for days upon its return and notice it starts chewing or "biting" the underside of its front leg (the portion abt 4" beneath its paw where there is another lump..)

3 days ago saw that there is a small open wound and can see the bone inside.(no bleeding), then yesterday noticed that both front legs are being "bitten".It just keep licking the area.

So today sent it to Vet again and was told that wound was not serious yet and clean and offer medication to it again. Then Vet put a Cone around its neck to prevent it from chewing further.

Question:

1) What can i do to help it recover fast so that it can walk again.

2) What causes it to bite itself?

3) Is it that dog is already old and this is its symptom ?

4) Can be be fully cure?

Your precious advise please. Thanks

Simon