What's My Liability as Expert Witness?

Dr. Trial has been hired as an expert witness to defend a dermatologist in a medical malpractice case. He rendered his expert opinion stating that he would have performed a dermatologic surgical procedure in a certain manner, even though such an approach was not routinely performed by the dermatologic community. The defendant dermatologist lost the case. His attorney is convinced that the case was lost because Dr. Trial did not perform well on cross-examination. Should Dr. Trial be concerned that he will now be sued?