Vaidyanatham is located at Deogarh in Bihar.

The temple structure has a great amount of woodwork.  The main sabha mandapam has several huge (wide as well as tall) pillars.  There are twenty two other temples in the temple complex.  The top of the Siva Lingam is slightly bent.  It is said that once Ravana, the king of Lanka, prayed to Lord Siva to make his capital of Lanka invincible.  After severe penance, he received the Aathma Lingam from Siva.  Unable to carry the huge Lingam, Lord Siva made the Lingam into two halves & placed it in a kavadi.

As Ravana was carrying this back to his Lanka, Lord Varuna caused his stomach to be filled with water.  Ravana was desperate to releive himself.  Seeing Lord Ganesha in the form of a brahmin boy, he gave it to him to hold (Lord Siva had said that the Aathama Lingam could not be placed on the ground, for wherever it was placed, it would take root).  Before Ravana could get back, Lord Ganesha put the Aathmalingam down.  The enraged Ravana tried hard to pluck the Lingam from the ground.  One half exists in Kokarnam.  Ravana started severe penance to Lord Siva, plucking & throwing one head after the other into the homa gundam.  Lord Siva revived him by putting his heads back in place.  Because of this role of Siva as a healer, as a physician, he came to be called Vaidyanathan (Vaidyan - physician).
 

The sacred shrine enshrining the SIvalinga with the marks of club on the top lies in Parli and it is one of the twelve Jyotirlingas adored over centuries.  Surprisingly enough, many places in India are claiming this honour; and strange to hear they are also called Vaidyanath temples - the temples at Deogarh in the Santhal Pargans in Bengal, at Gangakhed in Maharashtra, at Kiragram and at Dakhoi.
This information in italics is from the book "That Lord Siva to be adored" by Prof.K.K.Moorthy