Similar to what happen my 20 month old son ah. He got fever 3 weeks ago ... 102F - 103F for 3 days, then get back to normal in the 4th day, and follow with rash (lot of red spot on his neck & back) ... that's Roseola ah! The doctor said always happen to 4 month - 4 year old kid.
Have u tried to go to a public hospital and request that your baby be hospitalized? You'll be more relieved and less worried if the baby can stay in the hospital.