This could be a symptom of edema (also spelled oedema) or might be leaf scarring from the feeding damage of mites. Mites are sometimes common indoor plant pests because they can thrive in the drier (low-humidity) air and lack of rain, which would otherwise knock some of the mites off of the leaves.  Treatment with either horticultural oil or insecticidal soap, as directed on the product label, should reduce their numbers, though it may take several applications to get them all. (Don't use a home remedy of soap or oil, use only sprays that are manufactured and registered as pesticides for indoor plants, organic or otherwise.)

Leaves don't heal damage, but the plant will eventually shrivel and shed the injured leaves when it's producing replacement growth. In the meantime, you can keep them or selectively remove the worst of them as you wish.

Jade and other houseplant succulents don't want to be watered too minimally, and this plant's leaves do look not fully hydrated. (It's hard to tell, though, since their floppiness could be due to insufficient light instead. Jade needs bright light to thrive.) You don't want to water plants too sparingly because this won't fully saturate the soil and allow all the roots to absorb water. Roots which receive too little water can eventually die back, even on drought-tolerant plants, leaving them with too few healthy roots to support good nutrition and growth.

Instead, water jade and other succulents just like other houseplants, only less often, because succulents prefer to get drier between waterings than other tropicals. This means that you need to apply enough water volume so that extra water freely drains out of the pot's drainage holes. Doing so over a sink is the most practical way so it can drain unhindered, but if a pot is too cumbersome to move off of a saucer, be sure to empty that saucer right away when the pot is done draining. You don't want it sitting on the puddle of collected water because it can re-absorb into the soil and drown roots.

To know when it should need water, you can feel the soil about an inch or two beneath the surface (depending on how deep this pot is, since we can't really see its size). If moist to the touch, the watering can wait. If pretty dry, the plant can be watered then or soon. How often this occurs will depend on the plant's stage of growth, the time of year, and conditions in the home (air humidity, light levels, airflow). It's better to monitor the plant by touch (or feeling how heavy or light the pot is) rather than relying on a schedule for watering, though you can certainly at least check on it on a schedule.

If the plant isn't in a pot with drainage, transplant it into one that does have drain holes. (Or use a well-drained plastic pot set inside of a larger undrained decorative pot, but treat that outer pot like a saucer and empty it of collected water as soon as you're done watering.)

Another risk of not thoroughly watering a plant when watering is needed is that excess "salts" (the minerals in tap water and fertilizer, not necessarily sodium) don't leach out of the pot with the drained water. As they build up over time, these residues can injure roots, which then won't function properly. Replacing the potting mix every year or two is also helpful to keep roots healthy and eliminate residue buildup, but the primary method of delaying this buildup is to wet the soil enough when watering that you have extra water drain it away.

Miri

Thank you so much Miri.  OMG I need to replant this for sure with new soil and provide proper drain. Right now it is in a bowl and has no drainage.  I am surprised that this plant survived all these years.  Poor thing.   I am on it tomorrow.

You're welcome!