A sudden fever, severe throat tightness making it hard to swallow, and a headache suggest a throat infection, such as strep throat. While Vicks Vaporub can be soothing, it won't treat the underlying cause. It is very important that she sees a healthcare professional promptly for an evaluation, especially since swallowing liquids is difficult. To help her feel more comfortable now, she can take generic paracetamol or ibuprofen for the pain and fever. Please encourage her to take small, frequent sips of water to stay hydrated.