There are various types of hair loss that will require different treatment approaches. You should consult a dermatologist, plastic surgeon or aesthetic doctor with special interest in hair to help you with your concern. They should provide you with a detailed consultation, examination, necessary tests as well as advice for treatment options.
From the picture, you appear to be suffering from spot balding (otherwise known as alopecia areata). This can be treated with topical medications and injections to the scalp with variable success rates in different individuals. All the best!
