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It is okay. You do not need to rush to the dentist. The clinical scenario of teeth that you told indicates that most probably this gum recession is caused by yourself. You brush like giving a slight high power stroke on right and left bicuspids and then with normal force on rest of the teeth. Because of high-pressure stroke, gums in that particular area goes down, causing sensitivity of tooth.
Another cause could be plaque or tartar around that particular tooth causing gums infection that results in receding gums. But still, I think it is your brushing technique that is the main cause of receding gum. Tell me about it. You just have to change your brushing technique, do not do harsh brushing in that area. Take a soft bristle tooth brush. Avoid severe hot or cold food stuff till you visit your dentist. Rest treatment will be done later by the dentist and that could be scaling or filling of abrasion. Stay happy and blessed. Take care.