It looks healthy to me! Id replant it in a pot one size up from this one, a pot with a drainage hole, preferably a terracotta pot. Get a succulent soil and mix perlite in 50/50 mix. Lots of morning sunshine, no all day blazing sun however. It probably only needs to be watered every 2 or 3 weeks. Stick a chop stick down to the bottom of the pot to check for moisture, water when the stick comes out bone dry. During the winter it will probably only need water every 5 or 6 weeks, cacti go dormant in winter.Any saving this plant? It was left outside on the street with a sign asking for a new home so I took it!
But I'm pessimistic about it's health.
Golden lace cacti? Not sure? Any advice?