Is it obligatory to inform someone of the existence of the name of Allah, Exalted and Glorified is He, within your chest, or is it preferable to conceal that?

If the name of Allah appears on a woman's skin, the ruling regarding informing her of it or concealing it depends on her intention, purpose, and the benefit that results from it. Concealing it may be better. The 'awrah of a woman in front of another woman is from the navel to the knee. It is permissible to look at the rest of her body except for this area, as long as there is no lust or fear of fitnah (temptation/strife).