Hi,
The white bumps are likely milia (“oil” seeds) forming just beneath the skin. This may have occurred due to surface injury caused by the tattooing process. A close physical examination by your doctor is needed to confirm the diagnosis.
After confirming the diagnosis, the milia may be removed by making a small nick on the skin and extracting the milia seed under topical anaesthesia.
Hope this helps!
Related: The Ultimate Guide to Tattoo Removal in Singapore