Hello! Welcome and thank you for asking on HCM! I understand your concern and would explain that your symptoms may be related to anxiety. Is your tachycardia persistent? What is your actual heart rate? What were your blood pressure values, during having a fast heartbeat? An allergy would not cause just tachycardia, but also other symptoms like skin rash, itching, low blood pressure, etc. Based on what you refer, from your repeated blood tests, an infection which could be related to tachycardia has been excluded. So there is nothing to worry about! You can continue with your tattoo. Hope to have been helpful! Greetings! Dr. Iliri