How to predict on new text

i just trained my nlp model to predict classes i have to predict around 1300 different classes with given text i don’t get how to predict float values from a given text
for exi have text --i had fever last night and o take this pill and it cause headache it’s target is 8.2555656
something like this and when i see my data it’s about 1300 different target value some of them exists only once how to make trained such model