Hi there Thank you for your question. If your friend developed the bruises without being hurt, it is important for him to visit his doctor. This suggests a bleeding disorder. If he bleeds easily from his gums when brushing his teeth, it is also suggestive of a bleeding problem. The doctor will run a blood test to check his bleeding profile ie whether his blood has enough platelets to clot. Other blood tests might also be done based on the results. If the bruises are on the skin that was exposed to cleaning chemicals, he could be experiencing chemical burns or contact dermatitis. This is easily treated with topical antiseptic creams (silver sulfadiazine) for burns and anti histamine (allergex) with topical steroids for contact dermatitis. If this is the cause, he should wear gloves when cleaning so that he does not expose himself to the chemicals. If in doubt, and bruises are developing spontaneously anywhere on the body, I recommend visiting the doctor for the blood tests i mentioned above. Thank you. Keep well.