Tex. Human Resources Code § 36.115

(a) A person, including an employee, contractor, or agent, who is discharged, demoted, suspended, threatened, harassed, or in any other manner discriminated against in the terms and conditions of employment because of a lawful act taken by the person or associated others in furtherance of an action under this subchapter, including investigation for, initiation of, testimony for, or assistance in an action filed or to be filed under this subchapter, or other efforts taken by the person to stop one or more violations of Section 36.002 is entitled to:

(1) reinstatement with the same seniority status the person would have had but for the discrimination; and

(2) not less than two times the amount of back pay, interest on the back pay, and compensation for any special damages sustained as a result of the discrimination, including litigation costs and reasonable attorney's fees.

(b) A person may bring an action in the appropriate district court for the relief provided in this section.

(c) A person must bring suit on an action under this section not later than the third anniversary of the date on which the cause of action accrues. For purposes of this section, the cause of action accrues on the date the retaliation occurs.