I have a red mark with a crusty centre on my breast on my areola. no pain or itchiness, has just come up today.

? Folliculitis: It is not feasible to provide a meaningful opinion without examining you, however, what you described suggests inflammation of a hair follicle. You may apply warm compress and apply an over the counter topical antibiotic like Neosporin. For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form. Practice safe sex, if you have sex. Get HPV vaccine

Nipple eczema?: Sounds like a likely diagnosis but also skin infection or other breast conditions may need to be considered here. Recommend GP assessment as may require an examination to sort this out rather than simply viewing images via a virtual consult.