It could be that since she is starting to run a fever (low grade) and the drainage has some color to it, she could be starting to get a return of her sinus infection. The hydroxine dries up and secretions and makes her sleepy which is why it is working when she sleeps.That is a good thing.
The other things you are doing are right on target. Something you can try is a cough syrup for kids that contains dextrmethorphan like pedicare longacting cough or some delsym liquid. You may have to ask the pharmacist for these since they may be behind the counter but should not require a prescription. If her nose seems really congested, you can try using saline nasal spray or drops for children, then use a bulb syringe to suction the mucus out of her nose if she is unable to blow it out.
Use acetaminophen for the fever. If her symptoms continue, her fever stays, or her drainage continues to stay colored, I would not hesitate to have the doctor see her again in case her sinus infection is back.
I hope this information is helpful. I am here to help.
Please click the accept button if this information is helpful. If you are very satisfied, a bonus is welcomed. Please let me know if you have any more questions or need anything. As a mother, grandmother, & nurse, I understand what you are going through right now. Try to get some rest for yourself as well so you will have the strength to take care of both you and your child. Thank you. Prayers for you.