Yes, they are painful.But local anaesthetic solution is given to reduce pain.
The effect lasts 2 to 3 weeks.
The number of sittings would depend upon the skin concern. However, usually 4-6 sittings are given at a gap of 4 weeks.
As a general rule, we do not advise to take time off work or rest. However this advice does vary depending on what area is being injected.