is this still 4 month sleep regression??

so my LO is 4.5 months. he has 2 more days left of his 4th leap. he had his shots on the 25th, and for two weeks straight he slept amazing! from 10 to 7! two weeks before that he'd wake up ever couple of hours. now, starting last week, he's been teething, you can see the white gums, they're slowly making its way and he's been in pain. and now he wakes up 4-5 times a night, sometimes he's up for two hours, half asleep, but won't go back in his bassinet. I switched from Tylenol to Motrin yesterday, he slept for 3 hours (on me) in the afternoon. all he does is scream and cry during the day. I don't know what to do anymore. I'm traveling alone with him on Saturday by plane and I'm so nervous bc at the time I booked a good time for the flight, but now I don't know. it's only an hour and fifteen minutes flight, but still. any advice? does it get better?