Spider veins can be treated at any time except if you are pregnant and breastfeeding as a general rule.
The type of treatment is sclerotherapy where by a solution is injected into the spider veins to cause damage within the abnormal vessels. These vessels then fade over weeks to a few months.
If you have 1 or 2 little spots that are barely visible, it is best to wait and not get it treated immediately. It is often better to treat when there is a cluster or when there are many in a few different areas.
This is also because with any treatment we have to balance the possible complications and side effects of any treatment to the outcomes that want to be achieved.