Gaps after scaling is felt firstly because the tartar deposited in between teeth is removed out. Also there is some degree of gum recession after cleaning specially deeper cleaning/ root planning. This may seem unesthetic mainly in the front teeth. But there is no reason for swelling in the lip. There could be some Trauma or any other reason. It's a good idea to discuss the swollen lips with the dentist who carried out the scaling for you.

Usually if deposits are grade 3+,then even before the scaling and deep cleaning ,gaps between teeth develop due to gum infection but is not visible due to the deposits...After scaling, deposits are removed and the spaces start to be seen...But that does not mean that scaling should be avoided...Instead ,u should go for further gum treatment and after few months , closure of gaps if possible......