If you have the skills to change a battery yourself it should be fine. What model is it, there are plenty of TAG Heuer watches with 200m water resistance.
The 5 seconds jumping of the seconds hand is an indicator that the battery is about to run out and should be changed.
Thanks for your help about the 5 seconds skip. WA1201 are the #'s on the back of my older Tag . What does that mean? This watch is dead still no tick or tick skip.