HI, you are in the right spot to be asking questions about your new tank , as everyone has said ,get your water perams right , check that there is enough water movement in the tank ,take the Damsel out ,and above all be patient !!,that is a key element when keeping a marine aquarium, from the pics you posted I think that your tank will recover nicely if you keep your water right and give it time
good luck with your new tank