"You have a fever" is perfectly okay to use.

For instance if you go to "https://medlineplus.gov/fever.html", which is the website of the U.S. National Library of Medicine, you will see various usages of the word fever, including "you have a fever".

As for the list of expressions you gave, it is okay to say "I have a temperature, I have a bit of a temperature" informally. But formally what you need to say is "I have a high temperature; I have a bit of a high temperature."

"You have a fever" is perfectly okay to use.

For instance, if you go to "https://medlineplus.gov/fever.html", which is the website of the U.S. National Library of Medicine, you will see various usages of the word fever, including "you have a fever".

As for the list of expressions you gave, it is okay to say "I have a temperature, I have a bit of a temperature" casually. But "in proper English" what you need to say is "I have a high temperature; I have a bit of a high temperature." or even better "I have an elevated temperature; I have a bit of elevated temperature."

"You have a fever" is perfectly okay to use.

For instance if you go to "https://medlineplus.gov/fever.html", which is the website of U.S. National Library of Medicine, you will see various uses of the word fever, including "you have a fever".

As for the list of expressions you gave, it is okay to say "I have a temperature, I have a bit of a temperature" informally, collegially. But formally what you need to say is "I have a high temperature; I have a bit of a high temperature."

"You have a fever" is perfectly okay to use.

For instance if you go to "https://medlineplus.gov/fever.html", which is the website of the U.S. National Library of Medicine, you will see various usages of the word fever, including "you have a fever".

As for the list of expressions you gave, it is okay to say "I have a temperature, I have a bit of a temperature" informally. But formally what you need to say is "I have a high temperature; I have a bit of a high temperature."