Hello and welcome to HCM, Presence of vaginal rash and redness suggests an infection most probably fungal infection. is there any associated discharge? If discharge is present it should be sent for examination. Fungal infection can be treated with topical anti-fungals. Diarrhea is due to the gastrointestinal upset. An antibiotic can be taken after consulting your doctor. Norfloxacin is commonly prescribed for infective (bacterial) diarrhea, however take the drug prescribed by your treating doctor. Lump under the arms can be due to lymph node enlargement or rarely accessory breasts. However, these are only few causes, many other entities can cause such swelling. A fine needle aspiration of these lumps is needed. This procedure aspirates cells in the lesion. These cells are stained and observed under the microscope. This test will determine the origin and character of the lesion. So, consult your doctor and get the relevant investigations done. Thanks and take care Dr Shailja P Wahal