It’s the erupting third molar. The structure that you see on one side is the cusp of molar. It’s normal. Get. X ray (IOPA or OPG) dome to check it’s position. If the erupting third molar is favourable then it’s fine, other wise it needs to be extracted surgically.

It’s the wisdom tooth structure which is a normal structure but if it is causing you any discomfort or pain then get it extracted from the dentist

Hello.The picture the concerns that you have shared are suggestive of you having constant bite over the mucosa adjacent to your lower wisdom tooth mostly due to inflamed gums around your lower wisdom tooth (pericoronitis). Plus the bony structure that you are concerned of might be the root portion of the wisdom tooth which is becoming evident due to thinning of the mucosa over that region. While there isn't anything very serious or alarming now, but constant bite or trauma over any region in oral cavity can lead to serious problems afterwards like traumatic ulcer which can later have malignant changes if it doesn't heal. Therefore it will be advisable to consult your nearest Oral and Maxillofacial Surgeon and get your lower as well as upper wisdom tooth extracted.

These are bony structure of the wisdom tooth root section palpable under the mucosa of pterygomandibular raphe. It's normal finding. Don't worry about it.