Sleep must be guaranteed. Don't always give yourself a hint of lack of rest or an excuse for complaining. Wear an eye mask and earplugs after staying up late (the pineal gland secretes melatonin to promote sleep), slowly calm down and have a good sleep. You couldn't sleep before because your biological clock was disturbed and your body hasn't calmed down from the excitement of staying up late. This is to relax yourself, listen to some music and drink some milk, and stop thinking about homework or staying up late. You will get used to it more and then fall asleep easily.
Moreover, people's sleep is staged, each segment is 1.5~2 hours, and the first cycle at night is generally 2 hours. You can take the time to test yourself: set the alarm clock for two hours, and then go to sleep 10 minutes earlier or later every time. The most refreshing time when you wake up is your best sleep time. This cycle should be more than three times a day, and it is best to share the same bed. If you must stay awake in the middle of the night, it is ok to be apart.
If you have an oral ulcer, vitamin B supplementation is generally enough. If you can't supplement it, it should be caused by poor rest, indicating that you really need to adjust yourself. Watching more lights can help you stay awake when staying up late, so don't drink coffee. It will dehydrate your skin, so pay attention to drink plenty of water. If you get enough sleep, your skin will definitely get better. Come on ~