lexus es 350 changed battery in key fob- now alarm does not shut off and cannot open doors

Are you sure you put the correct replacement battery in? And polarity is correct? No foreign objects, however small got in to fob...causing a short? All these questions I ask....it seems your fob is sending a non-stop 'panic' signal to the car. What about another remote fob for same car...does the same.?....if not maybe the remote got damaged accidentally with battery change or has just gone faulty. Suggest making sure it's the right battery and while the fob is unsnapped if you can find some compressed air to blow in to innards. A good one would be aerosol computer/printer canned air

I know the battery is correct because dealer sent to me- just purchased the car 1 week ago- 1 fob worked, the other was dead- they sent me a battery and said to replace it and it should work- so something is wrong