1. Stick to unilateral movements that dumbbells and cables allow.
2. Always remember, WEAK SIDE RULE: never initiate a set with the strongest arm, that way when the weak arm dies first, you won't do more with the strong one thus adding to the imbalance.
3. Focus more on the "negative" portion of your reps with the weak arm. Good way to regain strength.
4. Try doing 1 &1/3 rep ranges with the weaker arm.
5. Give it time! It'll come back.
Good luck