Thanks for query,
You have a tight prepuce.
The bumps you talk about is stigma that is a collection of material over glans
due to not cleaning the part properly as skin cannot retracted.
Just try to retract the skin by daily applying warm water on it ,remove all stigma ,don't pull it force fully other wise it may cause non retraction leads to Phimosis
If after cleaning it & after pulling exercise for about 4=6 weeks you will still not able to retract it you need to go for circumcision
operation to remove the skin.