Sev is trying to vomit - not regurgitate.
I believe it would be best for you to take Sev to an Avian Vet for a proper diagnosis and treatment plan.
When a budgie shows symptoms of being sick - it is usually more ill than one thinks.
When you rely on anyone who has not had training in Avian diagnosis and care, you may be delaying effective treatment.
This can prolong suffering that may be avoidable.
The bird will often require a more intense, prolonged treatment with a poorer chance of full recovery than it would have if you seek prompt professional diagnosis and treatment at the first sign of illness.
If there are no Avian Vets near you, please find an Exotic Pet Veterinarian with experience in dealing with small birds.