Your symptoms suggest gastroenteritis with dehydration. First, immediately start drinking Oral Rehydration Salts (ORS) or coconut water to combat the dry mouth and loss of fluids. For stomach pain, an antispasmodic tablet like Dicyclomine can provide relief. For loose motions, a probiotic or Racecadotril is safe, but please avoid taking antibiotics without a doctor's prescription. I highly recommend consulting a physician for a proper evaluation. Seek immediate medical attention if you experience a high fever, bloody stools, or cannot keep liquids down. Rest well and prioritise hydration.

Your symptoms of vomiting, frequent loose stools, and rashes after travel are likely due to a stomach infection or food poisoning, possibly with an allergic reaction. Stay well hydrated with ORS, water, and coconut water, eat light foods like rice and banana, and avoid oily or outside food. For rashes, keep the skin clean and avoid scratching; an antihistamine may help if advised by a doctor. Since you have 7-8 loose stools and vomiting, it is important to consult a doctor promptly for proper treatment. Seek urgent care if you develop severe weakness, dehydration, high fever, or blood in your stools.