Platelet count alone is not sufficient to asses dangerous complications of Dengue.
Packed Cell Volume(PCV) is more important.Dont worry for Rash either, it's normal in Dengue.
Next Steps
Watch for any BLEEDING, Black stool, Coffee coloured Vomiting Red spots on skin, severe headache and pain abdomen & any difficulty in breathing.
Monitor for any fall in BP.
Health Tips
Proper Hydration & Nutrition is the KEY