Here are the self-care and exercise guidelines to follow after undergoing a mastectomy:

Preventing Swelling:
After breast cancer surgery involving the removal of breast tissue and lymph nodes, interference with local lymphatic flow can occur. This, along with subsequent radiation therapy causing tissue fibrosis, may lead to lymphedema in the arm. Early prevention is crucial.
Skin Protection and Care:
Avoid injuring the affected arm.
Apply a neutral, water-based, moisturizing lotion with good absorption multiple times a day to keep the skin hydrated and healthy.
When doing household chores, wear gloves to avoid contact with chemicals or sharp objects.
When going out, wear long-sleeved clothing to prevent insect bites or scratching that could damage the wound.
Trim your nails carefully, maintaining skin integrity by avoiding cutting too deep or too short.
If the skin is accidentally cut, stabbed, or bitten by insects, immediately rinse with normal saline and apply antibiotic ointment. Monitor for signs of inflammation. If redness, swelling, pain, or fever occurs, seek medical attention.
Avoid medical procedures on the affected arm, such as injections, blood draws, blood pressure measurements, etc.
Avoid lifting heavy objects or sudden excessive force: Avoid lifting heavy items for 1 to 2 weeks after surgery. After wound healing, gradually increase the weight lifted, but do not exceed 2 to 4 kilograms.
Break down household tasks and avoid overworking the arm. Rest if you feel a heavy, dragging sensation.
Avoid wearing jewelry on the affected arm, such as rings or bracelets.
Avoid high-temperature environments, such as hot springs, saunas, hot baths, steam rooms, especially for the affected arm.
Regular Self-Examination: Perform a self-examination at least once a week, comparing both arms from bottom to top. Check for changes in size, indentation from sleeves, and swelling under the armpit, lateral chest, and below the collarbone. If swelling persists for more than 3 days, seek rehabilitation treatment.
Home Exercises: Start with 10 repetitions, 3 to 5 times a day, gradually increasing the angle and repetitions.
Continue Previous Rehabilitation Exercises:
Maintain Good Posture: Sit with your body straight and chest up, ears aligned directly above shoulders, and shoulders relaxed. Avoid slouching.
Shoulder Lifts: Raise your shoulders to a tensed position and then relax.
Shoulder Rotations: Rotate your shoulders from front to back and back to front, each for about 10 repetitions.
Arm Raises: Hold your hands together and raise them from the front to a tensed position before lowering them.
Shoulder Joint Abduction: Bend your arms and raise them from the sides to a tensed position before lowering them.
Shoulder Joint External Rotation: Keep your elbows by your sides and rotate your forearms outward to a tensed position.
Arm Back Lifts: Place your hands on your buttocks and slowly move them upwards to a tensed position before lowering them.
Scapular Adduction: Let your hands naturally rest down while squeezing your shoulder blades inward (towards the spine), and slightly expand your chest while inhaling.
Wall Climbing Exercise: Using your fingers, climb up a wall until you feel tension, then lower them down. No need to pause before removing the drainage tube; after removing the tube, you can hold the position for 20 seconds before slowly lowering it.
General Aerobic Activities: Most mild exercises do not require limitations. Depending on your physical condition, engage in brisk walking, tai chi, line dancing, etc. Avoid sudden or excessive forceful movements. If you experience arm swelling or heaviness after exercise, avoid that particular movement and consult your doctor.
Scar Massage: After the stitches are removed, gently massage the scar using circular, horizontal, pulling, and rolling techniques to promote softening and smoothing of the scar.