I had asked for some further information and have not heard back.
Since the area of the tattoo is raised and itching, an allergy would be a primary concern. However, as I said above, it would be unusual for an allergy to arise 2 months after exposure. So, if the symptoms have only developed recently, it would be unusual to be an allergy to the ink.
It is possible that the raised skin could be due to excessive scar formation. If the scar formation is particularly severe, it would be called a keloid. Excessive scars and keloid formation are not common with a tattoo, but can occur. Although not common, when it does occur, it would be typical for it to take months to form.
If there is an allergy, a hydrocortisone cream is reasonable, and adding an oral antihistamine would be an option. There also are stronger steroid creams that are only available by prescription. If there is excessive scar formation, topical gels or vitamin D oil may help, but when it is more severe, it would usually need treatments by your doctor, such as injections of steroids into the scar, and in the worst cases, it may require excision,
If you can attach a picture, then I can provide additional comments.