Does it herm the calcium layer of teeth by scaling. just scaled last day my tooth's are so sensitive today mostly when drinking cold water?

Should not: The reason why we have to scale is because of tartar build up. The tartar builds up at the gum line and causes breakdown of the tissue and bone. As the tissue breaks down recession occurs. As the the gums recede the root of the tooth becomes exposed. The root does not have the insulating enamel and is much more sensitive this is what you are feeling. Hopefully it will calm down over time.

Scaling: Scaling is a procedure involving the instrumentation of your root surface to remove plaque and calculus. During this process, it can open up the dentinal tubules on your root, which can cause temporary sensitivity, like when drinking cold water.

No: It does not harm the enamel (calcium layer). You needed the scaling because of hard calcium deposits on the roots of the teeth. There is no enamel layer on the roots. Now that they are clean the root is exposed and sensitive. This is normal and should get better over time.