Articles are not substances or mixtures and so are not classed as cosmetic products. Depending on its intended function an article may be a general product or a medical device, etc.
General products are regulated under the General Product Safety Regulations 2005 (GPSR). Under the GPSR companies have an obligation to ensure that general products are safe in normal or reasonably foreseeable use. Guidance for businesses on general product safety is available on the gov.uk website.
If your product may be classed as a medical device, guidance on the regulation and enforcement of medical devices can be found on the Medicines and Healthcare products Regulatory Agency (MHRA) website.